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
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