A204656 Numbers n such that n!10+1 is prime.

0, 1, 2, 4, 6, 10, 16, 34, 46, 94, 146, 156, 166, 170, 194, 198, 206, 308, 456, 610, 614, 734, 1288, 1512, 1558, 2066, 2090, 2122, 3434, 3560, 3642, 3896, 4294, 4534, 4962, 5022, 5874, 8002, 9870, 11358, 11438, 13350, 15046, 16046, 20228, 25014, 30114, 35668, 38466, 46702, 48302

Offset

1,3

Comments

n!10 = product( n-10k, 0 <= k < n/10 ).

a(1)-a(51) proved prime by deterministic tests of PFGW. - Robert Price, Jun 08 2012

a(52) > 50,000. - Robert Price, Jun 08 2012

Links

Table of n, a(n) for n=1..51.

Ken Davis, Status of Search for Multifactorial Primes.

Ken Davis, Results for n!10+1.

Nathan Russell, n!10+2 results, primenumbers group, Jan 2012

Nathan Russell, n!10+2 results, message 23995 in primenumbers Yahoo group, Jan 17, 2012.

Prog

(PARI) for(n=0, 9999, isprime(prod(i=1, (n-2)\10, n-(10*i), n)+1)& print1(n", "))

Crossrefs

Sequence in context: A334213 A164142 A048833 * A070689 A339312 A091611

Adjacent sequences: A204653 A204654 A204655 * A204657 A204658 A204659

Keyword

nonn,hard

Author

M. F. Hasler, Jan 17 2012

Extensions

a(29)-a(51) from Robert Price, Jun 08 2012

Status

approved