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 A138872 #5 Mar 30 2012 17:33:54 %S A138872 22,44,1616,6464,409096,655536,262144,107824,115976,309056,811064, %T A138872 850864,343576,265064,520544,737504,223176,129536,953496,142304, %U A138872 239056,173776,140096,215736,224376,201256,427336,268104,260504,256656,373224,870944 %N A138872 Concatenation of first 3 digits and last 3 digits of n-th even superperfect number A061652(n). %C A138872 Also, concatenation of first 3 digits and last 3 digits of n-th superperfect number A019279(n), if there are no odd superperfect numbers. %Y A138872 Cf. A019279, A061652, A138866, A138877, A138870, A138871. %K A138872 base,nonn,less %O A138872 1,1 %A A138872 _Omar E. Pol_, Apr 02 2008 %E A138872 More terms from _Max Alekseyev_, Feb 11 2012