OFFSET
1,1
LINKS
Tim Johannes Ohrtmann, Table of n, a(n) for n = 1..2963
EXAMPLE
a(1) = 165 because this is the first squarefree composite number n such that at least one positive integer b except 0 exists such that for every prime factor p of n applies that p+b divides n+b (3): 165=3*5*11 and 6, 8, 14 all divide 168.
PROG
(PARI) for(n=2, 1000000, if(!isprime(n), if(issquarefree(n), f=factor(n); b=0; until(c==0 || b==n, b++; c=0; for(i=1, #f[, 1], if((n+b)%(f[i, 1]+b)>0, c++)); if(c==0, print1(n, ", "))))))
CROSSREFS
KEYWORD
nonn
AUTHOR
Tim Johannes Ohrtmann, Jun 23 2015
STATUS
approved