A215233 Primes of the form 4m^2 + 1 such that the next prime of this form is a record distance away.

5, 37, 677, 1601, 8837, 33857, 122501, 246017, 11492101, 12503297, 2058436901, 6844914757, 9813676097, 127566122897, 707119537217, 15058714869137, 779243651884097, 1641669426950401, 10965274367622437, 1269017804759665217, 4346851918104880901

Offset

1,1

Comments

Distance from 4m^2+1 to 4n^2+1 is measured as n-m.

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..26

Prog

(PARI) r=0; last=2; forstep(n=4, 1e9, 2, if(!ispseudoprime(n^2+1), next); if(n-last>r, r=n-last; print1(last^2+1", ")); last=n) \\ Charles R Greathouse IV, Apr 09 2013

Crossrefs

See A215234 for the next larger prime of the form 4m^2 + 1.

Cf. A214518 (record differences of m), A214519 (values of m).

Sequence in context: A095957 A354862 A121834 * A083846 A358887 A336241

Adjacent sequences: A215230 A215231 A215232 * A215234 A215235 A215236

Keyword

nonn,hard

Author

T. D. Noe, Aug 14 2012

Extensions

a(19)-a(21) from Charles R Greathouse IV, Apr 09 2013

Status

approved