OFFSET
0,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..25
FORMULA
a(n) = 1/8*(4^(n^2) + 2*4^(n^2/4) + 3*4^(n^2/2) + 2*4^((n^2+n)/2)) if n is even;
a(n) = 1/8*(4^(n^2) + 2*4^((n^2+3)/4) + 4^((n^2+1)/2) + 4*4^((n^2+n)/2)) if n is odd.
MATHEMATICA
Table[If[EvenQ[n], (4^n^2+2*4^(n^2/4)+3*4^(n^2/2)+2*4^((n^2+n)/2))/8, (4^n^2+2*4^((n^2+3)/4)+4^((n^2+1)/2)+4*4^((n^2+n)/2))/8], {n, 0, 10}] (* Harvey P. Dale, Aug 16 2021 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Vladeta Jovovic, May 15 2000
EXTENSIONS
Terms a(10) and beyond from Andrew Howroyd, Apr 15 2021
STATUS
approved