cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A195379 3.5-gap primes: Primes prime(k) such that there is no prime between 7*prime(k)/2 and 7*prime(k+1)/2.

Original entry on oeis.org

2, 137, 281, 521, 641, 883, 937, 1087, 1151, 1229, 1277, 1301, 1489, 1567, 1607, 1697, 2027, 2081, 2237, 2381, 2543, 2591, 2657, 2687, 2729, 2801, 2851, 2969, 3119, 3257, 3301, 3359, 3463, 3467, 3529, 3673, 3733, 3793, 3821, 3851, 4073, 4217, 4229, 4241, 4259, 4283, 4337, 4421, 4481
Offset: 1

Views

Author

Vladimir Shevelev, Sep 17 2011

Keywords

Crossrefs

Cf. A080192, A195270, A195271, A195377, A195325, A195329, A193507, A194186, A164368, A194598, A194658, A194659, A194674, A164288, A164294.

Programs

  • Mathematica
    Select[Prime[Range[1000]], PrimePi[7*NextPrime[#]/2] == PrimePi[7*#/2] &] (* T. D. Noe, Sep 20 2011 *)

Extensions

Corrected by R. J. Mathar, Sep 20 2011

A218561 4-gap primes: Prime p is a term iff there is no prime between 4*p and 4*nextprime(p), where nextprime=A151800.

Original entry on oeis.org

29, 71, 137, 197, 239, 269, 347, 419, 431, 641, 659, 809, 821, 1061, 1091, 1151, 1289, 1489, 1607, 1721, 1783, 1877, 1949, 1993, 2083, 2141, 2267, 2339, 2381, 2389, 2549, 2729, 2801, 2833, 2969, 2999, 3019, 3041, 3217, 3253, 3299, 3329, 3389, 3461
Offset: 1

Views

Author

Vladimir Shevelev and Peter J. C. Moses, Nov 02 2012

Keywords

Examples

			29 is in the sequence since there are no primes in the interval(4*29,4*31)=(116,124)

Links

Crossrefs

Cf. A195270, A195271, A195377, A195325, A195329, A195379.

Programs

Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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