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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A259978 Terms in A053177 that are relatively prime to 3.

Original entry on oeis.org

35, 95, 119, 143, 203, 215, 275, 299, 335, 395, 455, 515, 527, 539, 623, 635, 695, 707, 767, 779, 803, 899, 923, 935, 959, 1007, 1043, 1115, 1127, 1139, 1175, 1199, 1235, 1295, 1355, 1403, 1547, 1595, 1643, 1655, 1679, 1715, 1727, 1763, 1775, 1859, 1883, 1895
Offset: 1

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Author

N. J. A. Sloane, Jul 12 2015, following a suggestion from R. P. Boas, May 19 1974

Keywords

Crossrefs

Cf. A053177.

Programs

  • Mathematica
    Select[2 Prime@ Range@ 162 + 1, CompositeQ@ # && GCD[3, #] == 1 &] (* Michael De Vlieger, Jul 13 2015 *)
  • PARI
    isok(n) = (n % 2) && !isprime(n) && isprime((n-1)/2) && (gcd(n, 3) == 1); \\ Michel Marcus, Jul 28 2018

Formula

a(n) = 2*A275770(n) + 1. - Hilko Koning, Jul 23 2018

Extensions

More terms from Lars Blomberg, Jul 13 2015
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