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.

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A242773 The greater of twin primes p2 such that 2*p1 + p2 is a prime number (A174913) and also the lesser of other twin primes in A174913.

Original entry on oeis.org

7, 11491, 32971, 33331, 33601, 42841, 58111, 93811, 96331, 114601, 180181, 273001, 309541, 334891, 401311, 540541, 633571, 717091, 784351, 820411, 870241, 879691, 907141, 948091, 989251, 991621, 994561, 1020961, 1028581, 1044751, 1185661, 1189651, 1245451, 1253911
Offset: 1

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Author

Ivan N. Ianakiev, May 22 2014

Keywords

Comments

It seems that a(n) == 1 mod 10 for n > 1.
a(n) == 1 (mod 10) for n > 1 since if p2 == 3, 7 or 9 (mod 10) then 2*p1 + p2, p1, or 2*p1 + p2 + 2 is divisible by 5, respectively. - Amiram Eldar, Dec 31 2019

Examples

			a(1) = 7, 7 - 2 = 5 = A174913(1) and 2*A174913(1) + 7 = A174913(2).
		

Crossrefs

Programs

  • Mathematica
    Select[Range[10^6], And @@ PrimeQ[{#, # + 2, (p = 3*# + 2), p + 2, 3*p + 2}] &] + 2 (* Amiram Eldar, Dec 31 2019 *)

Formula

a(n) = A242772(n) + 2.
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