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 A305706 #13 Jun 10 2018 12:54:34 %S A305706 0,0,2,2,2,2,2,2,2,3,0,4,3,2,2,3,3,2,4,3,14,4,5,4,4,5,4,5,6,6,14,5,6, %T A305706 5,6,6,6,5,5,6,14,7,6,8,6,7,6,8,7,7,16,6,6,8,7,8,7,7,9,7,15,8,8,7,8,8, %U A305706 9,8,8,8,18,12,9,9,8,9,9,9,9,9,18,10,11,11,10,11,11,10,9,10,17,11,11,10,11,10,12,12,10,11,0 %N A305706 a(n) = smallest m such that the sum of digits of n^m is greater than n, or 0 if no such m exists. %C A305706 a(n) = smallest m such that A007953(n^m) > n, or 0 if no such m exists. %C A305706 If n is a term of A178501, then a(n) = 0. - _Felix Fröhlich_, Jun 10 2018 %o A305706 (PARI) a(n) = if(sumdigits(n) < 2, return(0), my(m=2); while(1, if(sumdigits(n^m) > n, return(m)); m++)) \\ _Felix Fröhlich_, Jun 10 2018 %Y A305706 Cf. A007953, A038206, A178501, A305707. %K A305706 base,nonn %O A305706 0,3 %A A305706 _Max Alekseyev_, Jun 08 2018