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 A033643 #5 Mar 30 2012 18:35:33 %S A033643 1,1,2,6,24,120,24,144,312,1080,4632,24240,9264,57744,134016,517536, %T A033643 2338176,12725952,7014528,45192384,111428352,469862208,2213733888, %U A033643 12478256064,8854935552,58767959808,152955661824,693938824704 %N A033643 Base 6 digital convolution sequence. %e A033643 Suppose base = 3 and a(0)..a(13) are 1 1 2 1 3 7 6 20 52 6 26 104 32 162. In base 3, 14 = 112, so we convolve the last three terms with 1, 1, 2 to obtain 104*1+32*1+162*2 = 460. %K A033643 base,nonn %O A033643 0,3 %A A033643 _David W. Wilson_