OFFSET
0,2
PROG
(PARI) T(n, k) = (n+1)*(k+1) - sum(i=0, n, sum(j=0, k, gcd(i, j)>1)); \\ A049627
a(n) = sum(i=0, n\2, T(2*i, n-2*i)); \\ Michel Marcus, Aug 06 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Sean A. Irvine, Aug 05 2021
STATUS
approved