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.

A114172 Triangle, read by rows, where the g.f. of column n, C_n(x), equals the g.f. of row n, R_n(x), divided by (1-x)^(n+1), for n>=0; e.g., C_n(x) = R_n(x)/(1-x)^(n+1).

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 5, 6, 1, 1, 7, 16, 9, 1, 1, 9, 31, 36, 12, 1, 1, 11, 51, 95, 66, 15, 1, 1, 13, 76, 199, 229, 106, 18, 1, 1, 15, 106, 361, 601, 467, 156, 21, 1, 1, 17, 141, 594, 1316, 1509, 844, 216, 24, 1, 1, 19, 181, 911, 2542, 3951, 3293, 1395, 286, 27, 1, 1, 21, 226
Offset: 0

Views

Author

Paul D. Hanna, Nov 15 2005

Keywords

Examples

			Triangle begins:
1;
1,1;
1,3,1;
1,5,6,1;
1,7,16,9,1;
1,9,31,36,12,1;
1,11,51,95,66,15,1;
1,13,76,199,229,106,18,1;
1,15,106,361,601,467,156,21,1;
1,17,141,594,1316,1509,844,216,24,1;
1,19,181,911,2542,3951,3293,1395,286,27,1;
1,21,226,1325,4481,8910,10193,6447,2155,366,30,1; ...
Where g.f. for columns is formed from g.f. of rows:
GF(column 2) = (1 + 3*x + 1*x^2)/(1-x)^3
= 1 + 6*x + 16*x^2 + 31*x^3 + 51*x^4 + 76*x^5 +...
GF(column 3) = (1 + 5*x + 6*x^2 + 1*x^3)/(1-x)^4
= 1 + 9*x + 36*x^2 + 95*x^3 + 199*x^4 + 361*x^5 +...
GF(column 4) = (1 + 7*x + 16*x^2 + 9*x^3 + 1*x^4)/(1-x)^5
= 1 + 12*x + 66*x^2 + 229*x^3 + 601*x^4 + 1316*x^5 +...
		

Crossrefs

Cf. A114173 (row sums), A114174 (central terms), A114175 (row sums-square).

Programs

  • PARI
    {T(n,k)=if(n