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 A067417 #26 Sep 30 2022 23:32:24 %S A067417 1,3,1,9,4,1,27,24,5,1,81,144,45,6,1,243,864,405,72,7,1,729,5184,3645, %T A067417 864,105,8,1,2187,31104,32805,10368,1575,144,9,1,6561,186624,295245, %U A067417 124416,23625,2592,189,10,1,19683,1119744,2657205,1492992,354375,46656,3969,240,11,1 %N A067417 Triangle with columns built from certain power sequences. %H A067417 Indranil Ghosh, <a href="/A067417/b067417.txt">Rows 0..125, flattened</a> %F A067417 a(n, m) = 1 if n = m; a(n, m) = (m+3)*(3*(m+1))^(n-m-1) if n > m >= 0. %F A067417 G.f. for column m: (x^m)*(1-2*m*x)/(1-3*(m+1)*x). %e A067417 Triangle starts: %e A067417 1; %e A067417 3, 1; %e A067417 9, 4, 1; %e A067417 27, 24, 5, 1; %e A067417 ... %t A067417 A[n_,m_]:=If[n==m,1,(m+3)(3(m+1))^(n-m-1)]; Flatten[Table[A[n,m],{n,0,9},{m,0,n}]] (* _Stefano Spezia_, Sep 30 2022 *) %Y A067417 Cf. A009998 (triangle built from powers of (m+1)), A067402, A067410. %Y A067417 Columns m=0..8 are A000244, A067411, A067403, A067419, A067420, A067421, A067422, A067423, A067424. %K A067417 nonn,easy,tabl %O A067417 0,2 %A A067417 _Wolfdieter Lang_, Jan 25 2002