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A319073
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Square array read by antidiagonals upwards: T(n,k) = k*sigma(n), n >= 1, k >= 1.
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4
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1, 3, 2, 4, 6, 3, 7, 8, 9, 4, 6, 14, 12, 12, 5, 12, 12, 21, 16, 15, 6, 8, 24, 18, 28, 20, 18, 7, 15, 16, 36, 24, 35, 24, 21, 8, 13, 30, 24, 48, 30, 42, 28, 24, 9, 18, 26, 45, 32, 60, 36, 49, 32, 27, 10, 12, 36, 39, 60, 40, 72, 42, 56, 36, 30, 11, 28, 24, 54, 52, 75, 48, 84, 48, 63, 40, 33, 12
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..78.
Index entries for sequences related to sigma(n)
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EXAMPLE
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The corner of the square array begins:
A000203 A074400 A272027 A239050 A274535 A274536 A319527 A319528
A000027: 1, 2, 3, 4, 5, 6, 7, 8, ...
A008585: 3, 6, 9, 12, 15, 18, 21, 24, ...
A008586: 4, 8, 12, 16, 20, 24, 28, 32, ...
A008589: 7, 14, 21, 28, 35, 42, 49, 56, ...
A008588: 6, 12, 18, 24, 30, 36, 42, 48, ...
A008594: 12, 24, 36, 48, 60, 72, 84, 96, ...
A008590: 8, 16, 24, 32, 40, 48, 56, 64, ...
A008597: 15, 30, 45, 60, 75, 90, 105, 120, ...
A008595: 13, 26, 39, 52, 65, 78, 91, 104, ...
A008600: 18, 36, 54, 72, 90, 108, 126, 144, ...
...
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MAPLE
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with(numtheory): T:=(n, k)->k*sigma(n-k+1): seq(seq(T(n, k), k=1..n), n=1..12); # Muniru A Asiru, Jan 01 2019
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MATHEMATICA
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Table[k DivisorSigma[1, #] &[m - k + 1], {m, 12}, {k, m}] // Flatten (* Michael De Vlieger, Dec 31 2018 *)
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PROG
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(GAP) T:=Flat(List([1..12], n->List([1..n], k->k*Sigma(n-k+1))));; Print(T); # Muniru A Asiru, Jan 01 2019
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CROSSREFS
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Another version of A274824.
Antidiagonal sums give A175254.
Main diagonal gives A064987.
Row n lists the multiples of A000203(n).
Row 1 is A000027.
Initial zeros should be omitted in the following sequences related to the rows of the array:
Row 2-5: A008585, A008586, A008589, A008588.
Rows 6 and 11: A008594.
Rows 7-9: A008590, A008597, A008595.
Rows 10 and 17: A008600.
Rows 12-13: A135628, A008596.
Rows 14, 15 and 23: A008606.
Rows 16 and 25: A135631.
(Note that in the OEIS there are many other sequences that are also rows of this square array.)
Cf. A000203, A237593, A319526.
Sequence in context: A353659 A246982 A258215 * A129601 A340579 A187566
Adjacent sequences: A319070 A319071 A319072 * A319074 A319075 A319076
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KEYWORD
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nonn,tabl,easy
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AUTHOR
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Omar E. Pol, Sep 22 2018
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STATUS
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approved
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