A128620 Row sums of A128619.

1, 1, 4, 6, 15, 24, 52, 84, 170, 275, 534, 864, 1631, 2639, 4880, 7896, 14373, 23256, 41810, 67650, 120406, 194821, 343884, 556416, 975325, 1578109, 2749852, 4449354, 7713435, 12480600, 21540304, 34852944, 59917826, 96949079, 166094370, 268746336

Offset

0,3

Comments

Diagonals sums of A199512. - Philippe Deléham, Dec 01 2013

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

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

Formula

a(n) = floor((n+2)/2)*Fibonacci(n+1). - Philippe Deléham, Dec 01 2013

G.f.: (1 - x^2 + x^3)/((1 + x - x^2)*(1 - x - x^2)^2). - Bruno Berselli, Dec 02 2013

Example

a(5) = 15 = sum of row 5 in A128619: (5 + 0 + 5 + 0 + 5).

Mathematica

LinearRecurrence[{1, 4, -3, -4, 1, 1}, {1, 1, 4, 6, 15, 24}, 40] (* or *)
Table[Floor[(n+2)/2] Fibonacci[n+1], {n, 0, 40}] (* Bruno Berselli, Dec 02 2013 *)

Prog

(PARI) a(n)= ((n+2)\2) * fibonacci(n+1); \\ Michel Marcus, Dec 02 2013
(Magma) [Floor((n+2)/2)*Fibonacci(n+1): n in [0..40]]; // G. C. Greubel, Mar 15 2024
(SageMath) [int((n+2)/2)*fibonacci(n+1) for n in range(41)] # G. C. Greubel, Mar 15 2024

Crossrefs

Cf. A000045, A128619, A199512.

Sequence in context: A109731 A369437 A027631 * A358438 A045907 A254325

Adjacent sequences: A128617 A128618 A128619 * A128621 A128622 A128623

Keyword

nonn,easy

Author

Gary W. Adamson, Mar 14 2007

Extensions

More terms from Philippe Deléham, Dec 01 2013

a(31) corrected from Bruno Berselli, Dec 02 2013

Status

approved