A122611 G.f.: 1/(1 - 7 x + 15 x^2 - 6 x^3 - 11 x^4 + 6 x^5 + x^6).

1, 7, 34, 139, 516, 1802, 6039, 19657, 62634, 196404, 608361, 1866462, 5683236, 17200871, 51807242, 155421557, 464755958, 1386055506, 4124569714, 12251283960, 36334754000, 107624090145, 318444202635, 941387240040

Offset

1,2

Links

Table of n, a(n) for n=1..24.

Peter Steinbach, Golden fields: a case for the heptagon, Math. Mag. Vol. 70, No. 1, Feb. 1997, 22-31.

Index entries for linear recurrences with constant coefficients, signature (7,-15,6,11,-6,-1).

Mathematica

b = {1, -7, 15, -6, -11, 6, 1}; p[x_] := Sum[x^(n - 1)*b[[8 - n]], {n, 1, 7}] q[x_] := ExpandAll[x^6*p[1/x]] Table[ SeriesCoefficient[ Series[x/q[x], {x, 0, 30}], n], {n, 0, 30}]

Crossrefs

Cf. A066170.

Sequence in context: A000418 A055852 A319405 * A326245 A219756 A014915

Adjacent sequences: A122608 A122609 A122610 * A122612 A122613 A122614

Keyword

nonn,easy

Author

Roger L. Bagula and Gary W. Adamson, Sep 20 2006

Extensions

Edited by N. J. A. Sloane, Sep 21 2006

Status

approved