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.

A377709 Numbers that have a record number of infinitary divisors that are powerful (A001694).

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%I A377709 #9 Nov 04 2024 20:50:03
%S A377709 1,4,8,36,72,128,216,1152,3456,27000,28800,86400,279936,432000,
%T A377709 4233600,6998400,21168000,34992000,148176000,342921600,1714608000,
%U A377709 8957952000,12002256000,197222256000,207467568000,438939648000,1071630000000,1452272976000,3072577536000,7501410000000
%N A377709 Numbers that have a record number of infinitary divisors that are powerful (A001694).
%C A377709 Indices of records in A360721.
%C A377709 The corresponding record values are 1, 2, 3, 4, 6, 7, 9, 14, 21, 27, 28, 42, 49, 63, 84, 98, ... (see the link for more values).
%H A377709 Amiram Eldar, <a href="/A377709/b377709.txt">Table of n, a(n) for n = 1..117</a>
%H A377709 Amiram Eldar, <a href="/A377709/a377709.txt">Table of n, a(n), A360721(a(n)) for n = 1..117</a>
%t A377709 f[p_, e_] := 2^DigitCount[e, 2, 1] - Mod[e, 2]; d[1] = 1; d[n_] := Times @@ f @@@ FactorInteger[n]; v = Cases[Import["https://oeis.org/A025487/b025487.txt", "Table"], {_, _}][[;; , 2]]; seq = {}; dm = 0; Do[If[(dk = d[v[[k]]]) > dm, dm = dk; AppendTo[seq, v[[k]]]], {k, 1, Length[v]}]; seq
%Y A377709 Cf. A001694, A037445, A360721.
%Y A377709 Subsequence of A025487.
%K A377709 nonn
%O A377709 1,2
%A A377709 _Amiram Eldar_, Nov 04 2024