OFFSET
0,2
LINKS
Indranil Ghosh, Table of n, a(n) for n = 0..1500
José Agapito, Ângela Mestre, Maria M. Torres, and Pasquale Petrullo, On One-Parameter Catalan Arrays, Journal of Integer Sequences, Vol. 18 (2015), Article 15.5.1.
Milan Janjić, Pascal Matrices and Restricted Words, J. Int. Seq., Vol. 21 (2018), Article 18.5.2.
FORMULA
MATHEMATICA
Table[(n + 11)*4^(n + 2) - (n + 5) Binomial[2 (n + 4), n + 4]/2, {n, 0, 20}] (* Michael De Vlieger, Feb 18 2017 *)
PROG
(Python)
import math
def C(n, r):
....f=math.factorial
....return f(n)/f(r)/f(n-r)
def A045894(n):
....return (n+11)*4**(n+2)-(n+5)*C(2*(n+4), (n+4))/2 # Indranil Ghosh, Feb 18 2017
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
STATUS
approved