A073434 - OEIS

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A073434

Primes p such that 2p+1 is prime and there are an even number of primes in the interval [p+1,2p+1].

2, 3, 5, 11, 23, 41, 53, 83, 131, 233, 239, 251, 359, 443, 491, 509, 641, 719, 743, 761, 809, 953, 1019, 1031, 1103, 1451, 1511, 1559, 1583, 1733, 1889, 1901, 1931, 1973, 2063, 2069, 2129, 2273, 2351, 2543, 2549, 2693, 2753, 2819, 2903, 2939, 2963, 2969

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..48.

MATHEMATICA

Select[Prime/@Range[500], PrimeQ[2#+1]&&EvenQ[PrimePi[2#+1]-PrimePi[ # ]]&]

CROSSREFS

Sequence in context: A079848 A329749 A237810 * A109551 A326393 A162278

Adjacent sequences: A073431 A073432 A073433 * A073435 A073436 A073437

KEYWORD

nonn

AUTHOR

Roger L. Bagula, Oct 03 2002

EXTENSIONS

Edited by Dean Hickerson, Oct 09 2002

STATUS

approved