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.

A130456 Triangle, read by rows of 2n+1 terms, where row n+1 is generated by taking partial sums of row n and then append a zero followed by the final term in the partial sums of row n, for n>=0, with T(0,0)=1.

Original entry on oeis.org

1, 1, 0, 1, 1, 1, 2, 0, 2, 1, 2, 4, 4, 6, 0, 6, 1, 3, 7, 11, 17, 17, 23, 0, 23, 1, 4, 11, 22, 39, 56, 79, 79, 102, 0, 102, 1, 5, 16, 38, 77, 133, 212, 291, 393, 393, 495, 0, 495, 1, 6, 22, 60, 137, 270, 482, 773, 1166, 1559, 2054, 2054, 2549, 0, 2549, 1, 7, 29, 89, 226, 496, 978
Offset: 0

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Author

Paul D. Hanna, May 26 2007

Keywords

Comments

Final term in row n equals A098746(n) = number of permutations of [1..n] which avoid 4231 and 42513.

Examples

			Triangle begins:
1;
1, 0, 1;
1, 1, 2, 0, 2;
1, 2, 4, 4, 6, 0, 6;
1, 3, 7, 11, 17, 17, 23, 0, 23;
1, 4, 11, 22, 39, 56, 79, 79, 102, 0, 102;
1, 5, 16, 38, 77, 133, 212, 291, 393, 393, 495, 0, 495;
1, 6, 22, 60, 137, 270, 482, 773, 1166, 1559, 2054, 2054, 2549, 0, 2549; ...
		

Crossrefs

Cf. A098746 (final term in rows).

Programs

  • PARI
    {T(n,k)=local(A=[1],B);if(n==0,if(k==0,1,0),for(j=1,n, B=Vec(Ser(A)/(1-x));A=concat(concat(B,0),B[ #B]));A[k+1])}