

A034850


Triangular array formed by taking every other term of Pascal's triangle.


1



1, 1, 2, 1, 3, 1, 6, 1, 5, 10, 1, 6, 20, 6, 1, 21, 35, 7, 1, 28, 70, 28, 1, 9, 84, 126, 36, 1, 10, 120, 252, 120, 10, 1, 55, 330, 462, 165, 11, 1, 66, 495, 924, 495, 66, 1, 13, 286, 1287, 1716, 715, 78, 1, 14, 364, 2002, 3432, 2002, 364, 14, 1, 105, 1365, 5005, 6435
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OFFSET

0,3


LINKS

Table of n, a(n) for n=0..64.
D. Dumont and J. Zeng, Polynomes d'Euler et les fractions continues de StieltjesRogers, Ramanujan J. 2 (1998) 3, 387410.


FORMULA

a(n) = A007318(2n) if both are regarded as integer sequences.  Michael Somos, Feb 11 2004


EXAMPLE

Triangle begins:
1;
1;
2;
1,3;
1,6,1;
5,10,1;
6,20,6;
1,21,35,7;


PROG

(PARI) {T(n, k) = if( k<0  k>n\4 + (n+1)\4, 0, binomial(n, 2*k + (n+1)\2%2))}; /* Michael Somos, Feb 11 2004 */


CROSSREFS

Cf. A007318, A034839.
Sequence in context: A022458 A084419 A119606 * A220377 A145969 A140352
Adjacent sequences: A034847 A034848 A034849 * A034851 A034852 A034853


KEYWORD

nonn,easy,tabf


AUTHOR

N. J. A. Sloane.


STATUS

approved



