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A357173
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Positions of records in A357171, i.e., integers whose number of divisors whose decimal digits are in strictly increasing order sets a new record.
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0
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1, 2, 4, 6, 12, 24, 36, 48, 72, 144, 336, 468, 504, 936, 1008, 1512, 2520, 3024, 5040, 6552, 7560, 13104, 19656, 39312, 78624, 98280, 196560, 393120, 668304, 1244880, 1670760, 1867320, 3341520, 3734640, 7469280, 22407840, 26142480, 31744440, 52284960, 63488880
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OFFSET
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1,2
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COMMENTS
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As A009993 is finite, this sequence is necessarily finite.
Corresponding records are 1, 2, 3, 4, 6, 8, 9, 10, 11, ...
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LINKS
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Table of n, a(n) for n=1..40.
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EXAMPLE
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a(6) = 24 is in the sequence because A357171(24) = 8 is larger than any earlier value in A357171.
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MATHEMATICA
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s[n_] := DivisorSum[n, 1 &, Less @@ IntegerDigits[#] &]; seq = {}; sm = 0; Do[If[(sn = s[n]) > sm, sm = sn; AppendTo[seq, n]], {n, 1, 10^4}]; seq (* Amiram Eldar, Sep 17 2022 *)
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PROG
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(PARI) isok(d) = Set(d=digits(d)) == d; \\ A009993
f(n) = sumdiv(n, d, isok(d)); \\ A357171
lista(nn) = my(r=0, list = List()); for (k=1, nn, my(m=f(k)); if (m>r, listput(list, k); r = m); ); Vec(list); \\ Michel Marcus, Sep 18 2022
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CROSSREFS
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Cf. A009993, A357171, A357172, A160218.
Similar sequences: A093036, A340548, A355595.
Sequence in context: A307122 A309015 A355579 * A349424 A134865 A140753
Adjacent sequences: A357169 A357171 A357172 * A357174 A357177 A357191
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KEYWORD
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nonn,base,fini,new
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AUTHOR
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Bernard Schott, Sep 17 2022
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EXTENSIONS
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More terms from Amiram Eldar, Sep 17 2022
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STATUS
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approved
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