OFFSET
1,1
COMMENTS
Hugh Williams asks if this sequence is infinite.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
R. K. Guy, editor, Western Number Theory Problems, 1985-12-21 & 23, Typescript, Jul 13 1986, Dept. of Math. and Stat., Univ. Calgary, 11 pages. Annotated scan of pages 1, 3, 7, 9, with permission. See Problem 85:16.
MAPLE
filter:= n ->
isprime(n) and numtheory:-factorset((n+1)/8) mod 12 subset {7}:
select(filter, [seq(i, i=7..10^5, 8)]); # Robert Israel, Dec 24 2020
PROG
(PARI) isok(p) = if (isprime(p) && (Mod(p, 8)== -1), my(r=(p+1)/8, f=factor(r)[, 1]); #select(x->(Mod(x, 12) == 7), f) == #f); \\ Michel Marcus, Dec 24 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 24 2020
EXTENSIONS
More terms from Michel Marcus, Dec 24 2020, who also added the initial term 7.
STATUS
approved