OFFSET
1,1
LINKS
David A. Corneth, Table of n, a(n) for n = 1..10000
EXAMPLE
21 is a term as 21 = 3*7 = 4^2+4+1; 21 is the product of two distinct primes and 21 is of the form k^2 + k + 1.
MATHEMATICA
f[n_]:=Last/@FactorInteger[n]=={1, 1}; Select[Array[ #^2+#+1&, 6!, 2], f[ # ]&]
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Apr 07 2010
EXTENSIONS
Name corrected by David A. Corneth, May 29 2023
STATUS
approved