A192226 Numbers n such that all integers in the interval (n-2*sqrt(sqrt(n)), n] are composite.

1, 28, 36, 96, 120, 121, 122, 123, 124, 125, 126, 146, 147, 148, 189, 190, 207, 208, 209, 210, 219, 220, 221, 222, 249, 250, 292, 302, 303, 304, 305, 306, 326, 327, 328, 329, 330, 346, 477, 478, 519, 520, 533, 534, 535, 536, 537, 538, 539, 540, 630, 672

Offset

1,2

Comments

a(14432) = 191913030 is probably the last term. Any further terms must be greater than 1.5 * 10^18. - Charles R Greathouse IV, Jun 30 2011

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..14432

Mathematica

Select[Range[700], NextPrime[#-2Sqrt[Sqrt[#]]]>#&] (* Harvey P. Dale, Jul 27 2011 *)

Prog

(PARI) is(n)=for(k=0, sqrtnint(16*n-1, 4), if(isprime(n-k), return(0))); 1 \\ Charles R Greathouse IV, Aug 26 2015

Crossrefs

Cf. A188817, A189025, A008995.

Sequence in context: A048023 A359529 A105710 * A323005 A080983 A179105

Adjacent sequences: A192223 A192224 A192225 * A192227 A192228 A192229

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jun 26 2011

Extensions

a(12)-a(13) added, a(53)-a(56) corrected by Charles R Greathouse IV, Jun 30 2011

Status

approved