OFFSET
1,1
FORMULA
a(n+1) = (floor(sqrt(9*10^n)) + (n mod 2))^2, a(2)=0. - Sascha Kurz, Mar 18 2002
a(2k+1) = 9 * 10^(2k) for k >= 0. - Bernard Schott, Mar 23 2021
PROG
(PARI) a(n) = if (n==2, 0, (sqrtint(9*10^(n-1)) + (n-1) % 2)^2); \\ Michel Marcus, Mar 23 2021
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Amarnath Murthy, Feb 09 2002
EXTENSIONS
More terms from Sascha Kurz, Mar 18 2002
STATUS
approved