OFFSET
1,2
COMMENTS
Numbers k such that there is no prime p such that gpf(k+p) = p.
Numbers k such that there is no prime factor p of k such that k+p is p-smooth.
LINKS
Jianing Song, Table of n, a(n) for n = 1..9826 (all terms <= 80000)
EXAMPLE
12 is a term since the prime factors of 12 are 2,3, and we have gpf(12+2) != 2 and gpf(12+3) != 3.
PROG
(PARI) gpf(n) = vecmax(factor(n)[, 1]);
isA354515(n) = if(n, my(f=factor(n)[, 1]); for(i=1, #f, if(gpf(n+f[i])==f[i], return(0))); 1, 0)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jianing Song, Aug 16 2022
STATUS
approved