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A195271 1.5-gap 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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

For a real r>1, a prime p is called an r-gap prime, if there is no prime between r*p and r*q, where q is the next prime after p. In particular, 2-gap primes form A080192 and 3-gap 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: A277208 A077217 A243183 * A120847 A244085 A019353

Adjacent sequences:  A195268 A195269 A195270 * A195272 A195273 A195274

KEYWORD

nonn

AUTHOR

Vladimir Shevelev, Sep 14 2011

STATUS

approved

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Last modified November 19 09:04 EST 2018. Contains 317348 sequences. (Running on oeis4.)