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.

A333677 Numbers whose divisors can be partitioned into two disjoint sets whose sums are consecutive Fibonacci numbers.

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%I A333677 #8 Apr 02 2020 06:54:05
%S A333677 1,2,66,70,18084,19180,24934,26715,5346390,8197798,8424178,9088863,
%T A333677 1874967204,1988601580,2585182054,2769837915
%N A333677 Numbers whose divisors can be partitioned into two disjoint sets whose sums are consecutive Fibonacci numbers.
%C A333677 Since the sum of divisors of each term is also a Fibonacci number, this sequence is a subsequence of A272412.
%F A333677 66 is a term since its divisors {1, 2, 3, 6, 11, 22, 33, 66} can be partitioned into the two disjoint sets, {2, 3, 6, 11, 33} and {1, 22, 66}, whose sums, 55 and 89, are 2 consecutive Fibonacci numbers.
%t A333677 fibs = Fibonacci @ Range[2, 40]; seqQ[n_] := MemberQ[fibs, DivisorSigma[1, n]] && Module[{d = Divisors[n], s}, s = Round[Plus @@ d/GoldenRatio]; c = CoefficientList[Product[1 + x^i, {i, d}], x]; c[[1 + s]] > 0]; Select[Range[10^5], seqQ]
%Y A333677 Cf. A000045, A000203, A083207, A272412.
%K A333677 nonn,more
%O A333677 1,2
%A A333677 _Amiram Eldar_, Apr 01 2020
%E A333677 a(13)-a(16) from _Giovanni Resta_, Apr 02 2020