OFFSET
1,2
COMMENTS
a(10), if it exist, is greater than 47; any corresponding primes would have more than 40,000 decimal digits. - Charles R Greathouse IV, Oct 16 2015
PROG
(PARI) stepA072181(k, n)=if(n<3, return(n)); my(f=factor(k), g=factor(n), p=Set(concat(f[, 1], g[, 1])), x=((f, p) -> my(i=setsearch(f[, 1]~, p)); if(i, f[i, 2], 1)), e=apply(q->x(f, q)*x(g, q), p)); factorback(concat(Mat(p~), e~))
for(n=1, 1e4, k=stepA072181(k, n); if(ispseudoprime(k+1), print1(n", "))) \\ Charles R Greathouse IV, Oct 16 2015
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Naohiro Nomoto, Apr 26 2003
STATUS
approved