OFFSET
1,1
LINKS
Tim Johannes Ohrtmann, Table of n, a(n) for n = 1..84
EXAMPLE
598 is even, composite and squarefree and at least one nonzero integer b exists such that for every prime factor p of n, p+b divides n+b (2): 598 = 2*13*23 and 4, 15, 25 all divide 600.
PROG
(PARI) n=0; until(n==1000000, n+=2; if(!isprime(n), if(issquarefree(n), f=factor(n); k=0; b=0; until(b==n, b+=2; c=0; for(i=1, #f[, 1], if((n+b)%(f[i, 1]+b)>0, c++)); if(c==0, k++)); if(k>0, print1(n, ", ")))))
CROSSREFS
KEYWORD
nonn
AUTHOR
Tim Johannes Ohrtmann, Sep 16 2015
STATUS
approved