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 A131727 #6 Aug 26 2015 00:41:48 %S A131727 1,2,7,16,40,98,237,574,1386,3346,8078,19502,47083,113668,274421, %T A131727 662510,1599442,3861396,9322235,22505868,54333972,131173812,316681596, %U A131727 764537004,1845755605,4456048214,10757852035,25971752284,62701356604 %N A131727 Pell numbers A000129 without last digit. %F A131727 a(n)=(A000129(n)-A131711(n))/10. - _R. J. Mathar_, Jul 17 2009 %p A131727 A000129 := proc(n) option remember ; if n <= 2 then n ; else 2*A000129(n-1)+A000129(n-2) ; fi ; end: A131727 := proc(n) floor(A000129(n)/10) ; end: seq(A131727(n),n=4..40) ; # _R. J. Mathar_, Oct 24 2007 %K A131727 nonn,base %O A131727 4,2 %A A131727 _Paul Curtz_, Sep 16 2007, Sep 27 2007 %E A131727 More terms from _R. J. Mathar_, Oct 24 2007