



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
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OFFSET

0,3


COMMENTS

Diagonals sums of A199512.  Philippe Deléham, Dec 01 2013


LINKS

Table of n, a(n) for n=0..35.
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


CROSSREFS

Cf. A000045, A128619, A199512.
Sequence in context: A300276 A109731 A027631 * A045907 A254325 A034299
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



