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.

A215195 Numbers n such that A143615(n) = sigma(n) where sigma(n) = A000203(n).

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%I A215195 #22 Nov 09 2014 08:05:53
%S A215195 1,598,1498,54797260
%N A215195 Numbers n such that A143615(n) = sigma(n) where sigma(n) = A000203(n).
%C A215195 a(5) (if it exists) > 10^8. - _Hiroaki Yamanouchi_, Sep 11 2014
%o A215195 (PARI) isok(n) = sum(m=1, n, if (gcd(n,m)==1, numdiv(m))) == sigma(n); \\ _Michel Marcus_, Nov 08 2014
%Y A215195 Cf. A000203, A143615.
%K A215195 nonn,more
%O A215195 1,2
%A A215195 _Naohiro Nomoto_, Aug 05 2012
%E A215195 a(4) from _Hiroaki Yamanouchi_, Sep 11 2014