cp's OEIS Frontend

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.

A101515 Symmetric square array, read by antidiagonals, such that the inverse binomial transform of row n forms the sequence: {C(n,k)*A101514(k), 0<=k<=n}, where A101514 equals the main diagonal shift right.

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%I A101515 #5 Jun 13 2017 22:17:09
%S A101515 1,1,1,1,2,1,1,3,3,1,1,4,7,4,1,1,5,13,13,5,1,1,6,21,35,21,6,1,1,7,31,
%T A101515 77,77,31,7,1,1,8,43,146,236,146,43,8,1,1,9,57,249,596,596,249,57,9,1,
%U A101515 1,10,73,393,1290,2037,1290,393,73,10,1,1,11,91,585,2486,5772,5772,2486,585
%N A101515 Symmetric square array, read by antidiagonals, such that the inverse binomial transform of row n forms the sequence: {C(n,k)*A101514(k), 0<=k<=n}, where A101514 equals the main diagonal shift right.
%C A101515 The main diagonal equals A101514 shift one place left. The antidiagonal sums form A101516.
%e A101515 Rows begin:
%e A101515 [_1,1,1,1,1,1,1,1,1,...],
%e A101515 [1,_2,3,4,5,6,7,8,9,...],
%e A101515 [1,3,_7,13,21,31,43,57,73,...],
%e A101515 [1,4,13,_35,77,146,249,393,585,...],
%e A101515 [1,5,21,77,_236,596,1290,2486,4387,...],
%e A101515 [1,6,31,146,596,_2037,5772,13987,29987,...],
%e A101515 [1,7,43,249,1290,5772,_21695,67943,181811,...],
%e A101515 [1,8,57,393,2486,13987,67943,_277966,951051,...],
%e A101515 [1,9,73,585,4387,29987,181811,951051,_4198635,...],...
%e A101515 The inverse binomial transform of the rows of this array are generated
%e A101515 from the products of the main diagonal with rows of Pascal's triangle:
%e A101515 BINOMIAL[1*1] = [_1,1,1,1,1,1,1,1,1,...],
%e A101515 BINOMIAL[1*1,1*1] = [1,_2,3,4,5,6,7,8,9,...],
%e A101515 BINOMIAL[1*1,1*2,2*1] = [1,3,_7,13,21,31,43,57,73,...],
%e A101515 BINOMIAL[1*1,1*3,2*3,7*1] = [1,4,13,_35,77,146,249,393,...],
%e A101515 BINOMIAL[1*1,1*4,2*6,7*4,35*1] = [1,5,21,77,_236,596,1290,...],
%e A101515 BINOMIAL[1*1,1*5,2*10,7*10,35*5,236*1] = [1,6,31,146,596,_2037,...],...
%o A101515 (PARI) T(n,k)=if(n<0 || k<0,0,if(n==0 || k==0,1,if(n>k,T(k,n), 1+sum(j=1,k,binomial(k,j)*binomial(n,j)*T(j-1,j-1));)))
%Y A101515 Cf. A101514, A101516.
%K A101515 nonn,tabl
%O A101515 0,5
%A A101515 _Paul D. Hanna_, Dec 06 2004