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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A141427 a(n) = phi(A067775(n)).

Original entry on oeis.org

1, 4, 10, 16, 22, 28, 30, 40, 46, 52, 58, 60, 70, 72, 82, 88, 100, 106, 112, 130, 136, 138, 148, 150, 156, 166, 172, 178, 180, 190, 196, 198, 210, 226, 232, 238, 240, 250, 256, 262, 268, 270, 280, 282, 292, 310, 316, 330, 336, 346, 352, 358, 366, 372, 382, 388
Offset: 1

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Author

Giovanni Teofilatto, Aug 06 2008

Keywords

Comments

Count of numbers smaller than and coprime to p for primes p such that p + 4 is composite.
Subsequence of A006093.

Crossrefs

Cf. A067775, A000010 (Euler totient function), A006093 (primes minus 1), A141426, A141515.

Programs

  • PARI
    {forprime(p=2, 400, if(!isprime(p+4), print1(eulerphi(p), ",")))} \\ Klaus Brockhaus, Aug 31 2008

Extensions

More terms from Robert G. Wilson v, Aug 18 2008
Edited by N. J. A. Sloane and Klaus Brockhaus, Aug 31 2008
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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