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.

A270540 Numbers that are equal to the number of their digits multiplied by the sum of the fifth powers of the digits.

This page as a plain text file.
%I A270540 #32 Apr 06 2016 02:01:25
%S A270540 0,1,1232,4100,268542
%N A270540 Numbers that are equal to the number of their digits multiplied by the sum of the fifth powers of the digits.
%C A270540 Terms up to 10^8.
%C A270540 No further terms after 10^7 since 10^k > k^2*9^5 beyond that point. - _Ray Chandler_, Apr 01 2016
%e A270540 4100 is a term because 4100 = 4*(4^5+1^5+0^5+0^5).
%t A270540 Position[ Table[ IntegerLength[ k] Sum[( Floor[k/10^n] - 10 Floor[k/10^(n + 1)])^5, {n, 0, IntegerLength@ k}] - k, {k, 1, 10^6}], 0] // Flatten = {1, 1232, 4100, 268542}
%t A270540 Select[Range[10^7],With[{id=IntegerDigits[#]},#==Length[id]*Plus@@(id^5)]&] (* _Ray Chandler_, Apr 01 2016 *)
%o A270540 (PARI) isok(n) = my(d=digits(n)); n == #d*sum(k=1, #d, d[k]^5); \\ _Michel Marcus_, Mar 25 2016
%Y A270540 Cf. A055014.
%K A270540 nonn,base,fini,full
%O A270540 1,3
%A A270540 _José de Jesús Camacho Medina_, Mar 18 2016
%E A270540 a(5) from _Michel Marcus_, Mar 25 2016