OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Jun Wang and Zhizheng Zhang, On extensions of Calkin's binomial identities, Discrete Math., 274 (2004), 331-342.
Index entries for linear recurrences with constant coefficients, signature (14,-84,280,-560,672,-448,128).
FORMULA
There is an explicit formula for the sum - see Wang and Zhang, p. 334.
From Chai Wah Wu, Jun 21 2016: (Start)
a(n) = 14*a(n-1) - 84*a(n-2) + 280*a(n-3) - 560*a(n-4) + 672*a(n-5) - 448*a(n-6) + 128*a(n-7) for n > 6.
G.f.: x*(-16*x^5 + 64*x^4 + 422*x^3 + 506*x^2 + 103*x + 2)/(1 - 2*x)^7. (End)
a(n) = 2^(n-7)*n*(21*n^5 + 61*n^4 + 55*n^3 + 15*n^2 - 28*n + 4). - Ilya Gutkovskiy, Jun 21 2016
E.g.f.: (1/4)*x*(8 + 246*x + 940*x^2 + 1015*x^3 + 376*x^4 + 42*x^5)*exp(2*x). - G. C. Greubel, May 24 2022
MATHEMATICA
LinearRecurrence[{14, -84, 280, -560, 672, -448, 128}, {0, 2, 131, 2172, 20386, 138580, 763824}, 30] (* Vincenzo Librandi, Jun 22 2016 *)
PROG
(Magma) [2^(n-7)*n*(21*n^5+61*n^4+55*n^3+15*n^2-28*n+4): n in [0..30]]; // Vincenzo Librandi, Jun 22 2016
(SageMath) [2^(n-7)*n*(21*n^5 +61*n^4 +55*n^3 +15*n^2 -28*n +4) for n in (0..40)] # G. C. Greubel, May 24 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jan 04 2004
STATUS
approved