OFFSET
1,1
LINKS
Daniel Starodubtsev, Table of n, a(n) for n = 1..1000
EXAMPLE
13 appears in the list because 13^2 + 1 = 170 = 2 * 5 * 17.
21 appears in the list because 21^2 + 1 = 442 = 2 * 13 * 17.
MATHEMATICA
PROG
(PARI) isok(k) = my(x=k^2+1); (omega(x)==3) && (bigomega(x)==3); \\ Michel Marcus, Mar 11 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
K. D. Bajpai, Apr 19 2016
STATUS
approved