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.
%I A225792 #10 May 16 2013 11:38:23 %S A225792 1,2,3,9,13,54,384,596,7289,18136,226871,1577601,5240465,13389981, %T A225792 130707763,157598052,617834651,998713177,4596574856 %N A225792 Numbers n such that the sum of first n nontrivial prime powers (A025475 excluding 1) is divisible by n. %C A225792 a(16) > 146306912. There are 146306912 nontrivial prime powers <= 2^63. - _Donovan Johnson_, May 16 2013 %C A225792 a(20) > 41.2*10^9. - _Giovanni Resta_, May 16 2013 %e A225792 The sum of first 9 nontrivial prime powers is 4 + 8 + 9 + 16 + 25 + 27 + 32 + 49 + 64 = 234. Because 234 is divisible by 9, the latter is in the sequence. %Y A225792 Cf. A025475, A225791. %K A225792 nonn,more %O A225792 1,2 %A A225792 _Alex Ratushnyak_, May 16 2013 %E A225792 a(12)-a(15) from _Donovan Johnson_, May 16 2013 %E A225792 a(16)-a(19) from _Giovanni Resta_, May 16 2013