A167578 The third column of the ED3 array A167572.

1, 17, 183, 2043, 26529, 398025, 6765975, 128556675, 2699661825, 62092533825, 1552309291575, 41912411683275, 1215458905032225, 37679245697871225, 1243414695550433175, 43519523831289457875, 1610222144582102522625

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..150

Formula

a(n) = (1/4)*(-1)^(n)*(2*n-7)!!*((8*n^4-20*n^3-22*n^2+55*n+12)+(32*n^5-80*n^4-80*n^3+200*n^2+18*n-45)*(sum((-1)^(k+n)/(2*k+1),k=0..n-1))).

Mathematica

Table[(1/4)*(-1)^(n)*(2*n - 7)!!*((8*n^4 - 20*n^3 - 22*n^2 + 55*n + 12) + (32*n^5 - 80*n^4 - 80*n^3 + 200*n^2 + 18*n - 45)*(Sum[(-1)^(k + n)/(2*k + 1), {k, 0, n - 1}])), {n, 1, 50}] (* G. C. Greubel, Jun 16 2016 *)

Crossrefs

Equals the third column of the ED3 array A167572.

Other columns are A167576 and A167577.

Cf. A007509 and A025547 (the sum((-1)^(k+n)/(2*k+1), k=0..n-1) factor).

Sequence in context: A066521 A055904 A116964 * A181401 A243419 A270497

Adjacent sequences: A167575 A167576 A167577 * A167579 A167580 A167581

Keyword

easy,nonn

Author

Johannes W. Meijer, Nov 10 2009

Status

approved