A200140 Central terms in odd-indexed rows of triangle A200171.

1, 7, -54, 827, -14012, 259898, -5116318, 105172355, -2234053248, 48692954312, -1083547583038, 24527041757402, -563187320485774, 13089954727844002, -307442412559624318, 7286803572075349907, -174090195438541310248, 4188665368980014572652, -101416065009218889929998, 2469364164437930871076352

Offset

1,2

Links

Table of n, a(n) for n=1..20.

Prog

(PARI) {a(n)=local(A=1+x); for(i=1, (2*n-1)^2+3*n, A=(1+x*A)*(1+x^(2*n-1)/(A+x*O(x^((2*n-1)^2+n))))); polcoeff(A, (2*n-1)^2+3*n-2)}

Crossrefs

Cf. A200171, A200172, A200173.

Sequence in context: A014509 A228415 A084065 * A298104 A289865 A182124

Adjacent sequences: A200137 A200138 A200139 * A200141 A200142 A200143

Keyword

sign

Author

Paul D. Hanna, Nov 13 2011

Status

approved