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 A138883 #3 Mar 30 2012 17:39:33 %S A138883 1,1,2,2,4,5,6,10,19,27,32,38,157,183,385,663,687,969,1280,1332,2917, %T A138883 2993,3376,6002,6533,6987,13395,25962,33265,39751,65050,227831,258715, %U A138883 378632,420921,895932,909525,2098960 %N A138883 Number of digits in n-th even superperfect number A061652(n). %C A138883 Also, number of digits in n-th superperfect number A019279(n), if there are no odd superperfect numbers. %F A138883 a(n)=A055642(A061652(n)). - _R. J. Mathar_, May 22 2008 %Y A138883 Cf. A019279, A028335, A061193, A061652. %K A138883 base,nonn %O A138883 1,3 %A A138883 _Omar E. Pol_, Apr 08 2008 %E A138883 More terms from _R. J. Mathar_, May 22 2008