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.

A291176 Numbers k such that s(k) = s(k-1) + s(k-2), where s(k) is the sum of proper divisors of k (A001065).

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%I A291176 #22 Jul 23 2021 02:08:28
%S A291176 3,8,20,146139,584835,44814015,1436395095,9988999095,25997557299,
%T A291176 193861767939,2105722150095,3921293253003,8234992646643
%N A291176 Numbers k such that s(k) = s(k-1) + s(k-2), where s(k) is the sum of proper divisors of k (A001065).
%C A291176 a(14) > 10^13. - _Giovanni Resta_, Feb 25 2020
%e A291176 s(146139) = 76581 = 75802 + 779 = s(146138) + s(146137), therefore 146139 is in the sequence.
%t A291176 s[n_]:=DivisorSigma[1,n]-n; Select[Range[10^6], s[#]==s[#-1]+s[#-2] &]
%Y A291176 Cf. A001065, A065557, A065900, A076136, A076251, A145469.
%K A291176 nonn,more
%O A291176 1,1
%A A291176 _Amiram Eldar_, Aug 19 2017
%E A291176 a(7)-a(10) from _Giovanni Resta_, Aug 29 2017
%E A291176 a(11)-a(13) from _Giovanni Resta_, Feb 25 2020