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 A125793 #5 Jun 14 2017 00:16:30 %S A125793 1,4,16,84,656,8148,167568,5866452,356855440,38315189204, %T A125793 7352635371152,2547660633170900,1607532367023451792, %U A125793 1860491404939092059092,3974085151281967171382928,15751822048486986712162264020 %N A125793 Column 3 of table A125790; also equals row sums of matrix power A078121^3. %C A125793 Triangle A078121 shifts left one column under matrix square and is related to partitions into powers of 2. %o A125793 (PARI) a(n)=local(p=3,q=2,A=Mat(1), B); for(m=1, n+1, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i || j==1, B[i, j]=1, B[i, j]=(A^q)[i-1, j-1]); )); A=B); return(sum(c=0,n,(A^p)[n+1,c+1])) %Y A125793 Cf. A125790, A078121; columns: A002577, A125792, A125794, A125795, A125796; diagonals: A125797, A125798. %K A125793 nonn %O A125793 0,2 %A A125793 _Paul D. Hanna_, Dec 10 2006