cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A357173 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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%I A357173 #20 Sep 18 2022 10:21:11
%S A357173 1,2,4,6,12,24,36,48,72,144,336,468,504,936,1008,1512,2520,3024,5040,
%T A357173 6552,7560,13104,19656,39312,78624,98280,196560,393120,668304,1244880,
%U A357173 1670760,1867320,3341520,3734640,7469280,22407840,26142480,31744440,52284960,63488880
%N A357173 Positions of records in A357171, i.e., integers whose number of divisors whose decimal digits are in strictly increasing order sets a new record.
%C A357173 As A009993 is finite, this sequence is necessarily finite.
%C A357173 Corresponding records are 1, 2, 3, 4, 6, 8, 9, 10, 11, ...
%e A357173 a(6) = 24 is in the sequence because A357171(24) = 8 is larger than any earlier value in A357171.
%t A357173 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 *)
%o A357173 (PARI) isok(d) = Set(d=digits(d)) == d; \\ A009993
%o A357173 f(n) = sumdiv(n, d, isok(d)); \\ A357171
%o A357173 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
%Y A357173 Cf. A009993, A357171, A357172, A160218.
%Y A357173 Similar sequences: A093036, A340548, A355595.
%K A357173 nonn,base,fini
%O A357173 1,2
%A A357173 _Bernard Schott_, Sep 17 2022
%E A357173 More terms from _Amiram Eldar_, Sep 17 2022