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

Author

N. J. A. Sloane, Dec 22 2017

Keywords

• nonn
• easy

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).

Crossrefs

Cf. A296368.

Programs

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

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)

Extensions

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

More terms from Rémy Sigrist, Dec 23 2017