OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..55
FORMULA
a(n) = A001045(binomial(n+2, 2)) = 2^binomial(n+2, 2)/3 - (-1)^binomial(n+2, 2)/3.
PROG
(Magma) [2^Binomial(n+2, 2)/3-(-1)^Binomial(n+2, 2)/3: n in [0..15]]; // Vincenzo Librandi, Jun 29 2011
(PARI) a(n)=2^binomial(n+2, 2)\/3 \\ Charles R Greathouse IV, Jun 29 2011
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Apr 23 2003
STATUS
approved