OFFSET
0,2
LINKS
Joan Serra-Sagrista, Enumeration of lattice points in l_1 norm, Inf. Proc. Lett. 76 (1-2) (2000) 39-44.
Index entries for linear recurrences with constant coefficients, signature (22, -231, 1540, -7315, 26334, -74613, 170544, -319770, 497420, -646646, 705432, -646646, 497420, -319770, 170544, -74613, 26334, -7315, 1540, -231, 22, -1).
FORMULA
a(m) = add(2^k*binomial(n, k)*binomial(m-1, k-1), k=0..n)+2^n*binomial((n+2*m)/2-1, n-1); with n=22.
MAPLE
C := (m, n) -> `if`(m=0, 1, 2^n*binomial((n+2*m)/2-1, n-1) + 2*n*hypergeom([1-m, 1-n], [2], 2)): seq(simplify(C(m, 22)), m=0..21); # Peter Luschny, Jul 18 2020
MATHEMATICA
n:=22; Table[Sum[2^k*Binomial[n, k]*Binomial[m-1, k-1], {k, 0, n}] + 2^n*Binomial[(n+2*m)/2-1, n-1], {m, 0, n+2}] (* Georg Fischer, Jul 18 2020 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, J. Serra-Sagrista (jserra(AT)ccd.uab.es)
EXTENSIONS
More terms from Georg Fischer, Jul 18 2020
STATUS
approved