

A195271


1.5gap primes: Prime p is a term iff there is no prime between 1.5*p and 1.5*q, where q is the next prime after p.


8



2, 5, 17, 29, 41, 79, 101, 137, 149, 163, 191, 197, 227, 269, 281, 313, 349, 353, 461, 463, 521, 541, 569, 593, 599, 613, 617, 641, 757, 769, 809, 821, 827, 857, 881, 887, 941, 1009, 1049, 1061, 1087, 1093, 1097, 1117, 1151, 1223, 1229, 1277, 1279, 1289
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OFFSET

1,1


COMMENTS

For a real r>1, a prime p is called an rgap prime, if there is no prime between r*p and r*q, where q is the next prime after p. In particular, 2gap primes form A080192 and 3gap primes form A195270.


LINKS

Table of n, a(n) for n=1..50.


MATHEMATICA

Select[Prime[Range[400]], PrimePi[3*NextPrime[#]/2] == PrimePi[3*#/2] &] (* T. D. Noe, Sep 14 2011 *)


CROSSREFS

Cf. A080192, A195270, A193507, A194186, A164368, A194598, A194658, A194659, A194674, A164288, A164294.
Sequence in context: A211548 A277208 A243183 * A077217 A120847 A244085
Adjacent sequences: A195268 A195269 A195270 * A195272 A195273 A195274


KEYWORD

nonn


AUTHOR

Vladimir Shevelev, Sep 14 2011


STATUS

approved



