A296909 Partial sums of A296368.

1, 4, 12, 24, 39, 59, 84, 112, 143, 179, 220, 264, 311, 363, 420, 480, 543, 611, 684, 760, 839, 923, 1012, 1104, 1199, 1299, 1404, 1512, 1623, 1739, 1860, 1984, 2111, 2243, 2380, 2520, 2663, 2811, 2964, 3120, 3279, 3443, 3612, 3784, 3959, 4139, 4324, 4512

Offset

0,2

Links

Rémy Sigrist, Table of n, a(n) for n = 0..1000

Reticular Chemistry Structure Resource (RCSR), The mcm tiling (or net)

Index entries for linear recurrences with constant coefficients, signature (3,-4,4,-3,1).

Formula

From Colin Barker, Dec 23 2017: (Start)

G.f.: (1 + x + 4*x^2 + 2*x^4 + x^5 - x^6) / ((1 - x)^3*(1 + x^2)).

a(n) = (-1/4-i/4)*((1-i) + (-i)^n - i*i^n) + 2*n + 2*n^2 for n>1, where i=sqrt(-1).

a(n) = 3*a(n-1) - 4*a(n-2) + 4*a(n-3) - 3*a(n-4) + a(n-5) for n>6.

(End)

Prog

(PARI) Vec((1 + x + 4*x^2 + 2*x^4 + x^5 - x^6) / ((1 - x)^3*(1 + x^2)) + O(x^50)) \\ Colin Barker, Dec 24 2017

Crossrefs

Cf. A296368.

Sequence in context: A008180 A008201 A008076 * A008102 A009902 A301058

Adjacent sequences: A296906 A296907 A296908 * A296910 A296911 A296912

Keyword

nonn,easy

Author

N. J. A. Sloane, Dec 22 2017

Extensions

Terms a(8)-a(20) and RCSR link from Davide M. Proserpio, Dec 22 2017

More terms from Rémy Sigrist, Dec 23 2017

Status

approved