OFFSET
1,1
COMMENTS
EXAMPLE
97^2 + 97 + 7^2 = 9555 = A136476(1) is an odd primitive abundant number, so a(1) = 97.
PROG
(PARI) is(x, n=x^2+x+1, f)={forstep(y=1, sqrtint(2*x), 2, sigma(n+=y*4-4, -1)>2 || next; for(i=1, #f=factor(n)[, 1], sigma(n\f[i], -1)>2 && next(2)); return(1))} \\ M. F. Hasler, Feb 22 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Pierre CAMI, Dec 31 2007
EXTENSIONS
Edited by M. F. Hasler, Feb 22 2017
STATUS
approved