A082463 - OEIS

A082463

Numbers n such that A072181(n) + 1 is prime.

1, 2, 3, 4, 5, 6, 7, 9, 10

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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

LINKS

Table of n, a(n) for n=1..9.

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

Sequence in context: A126072 A265570 A265554 * A368432 A194962 A072793

Adjacent sequences: A082460 A082461 A082462 * A082464 A082465 A082466

KEYWORD

hard,more,nonn

AUTHOR

Naohiro Nomoto, Apr 26 2003

STATUS

approved