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.

Showing 1-3 of 3 results.

A117591 a(n) = 2^n + Fibonacci(n).

Original entry on oeis.org

1, 3, 5, 10, 19, 37, 72, 141, 277, 546, 1079, 2137, 4240, 8425, 16761, 33378, 66523, 132669, 264728, 528469, 1055341, 2108098, 4212015, 8417265, 16823584, 33629457, 67230257, 134414146, 268753267, 537385141, 1074573864, 2148829917
Offset: 0

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Author

Keywords

Comments

a(3n) is even if n>0. - Robert G. Wilson v, Sep 06 2002
3 divides a(8n+1) and a(8n-1). - Enrique Pérez Herrero, Dec 29 2010

Crossrefs

Programs

Formula

G.f. (1-3*x^2)/((1-x-x^2)*(1-2*x)).
a(n) = A000079(n+1) - A099036(n) = A099036(n) + 2 * A000045(n). - Reinhard Zumkeller, Aug 15 2013

A074716 Numbers k such that 2^k - F(k) is prime, where F(n) is the n-th Fibonacci number.

Original entry on oeis.org

2, 4, 14, 23, 55, 80, 104, 286, 335, 383, 809, 1664, 2096, 2624, 4262, 13544, 14249, 19886, 35500, 40591, 42920, 50839, 56696, 114505
Offset: 1

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Author

Benoit Cloitre, Sep 04 2002

Keywords

Comments

1664 and above are pseudoprimes only. - Sam Handler (sam_5_5_5_0(AT)yahoo.com), Dec 26 2004
1664, 2096, 2624 and 4262 correspond to certified primes. (Primo 2.2.0 beta) - Ryan Propper, Aug 29 2005

Crossrefs

Programs

  • Mathematica
    Do[ If[ PrimeQ[ 2^n - Fibonacci[n]], Print[n]], {n, 1, 5000}]

Extensions

Edited by Robert G. Wilson v, Sep 06 2002
a(16)-a(20) from Sam Handler (sam_5_5_5_0(AT)yahoo.com), Dec 18 2004
a(21)-a(23) from Michael S. Branicky, May 19 2023
a(24) from Michael S. Branicky, Aug 03 2024

A292614 Numbers k such that 2^k - Lucas(k) is prime.

Original entry on oeis.org

14, 19, 25, 41, 46, 65, 136, 145, 185, 193, 290, 406, 481, 641, 761, 3481, 4873, 5360, 6682, 13579, 34120, 35384, 43070, 46744, 96014, 212521
Offset: 1

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Author

Amiram Eldar, Sep 20 2017

Keywords

Comments

a(26) > 139000. - Giovanni Resta, Sep 21 2017

Crossrefs

Programs

  • Mathematica
    Select[Range[0, 6000], PrimeQ[2^# - LucasL[#]] &]

Extensions

a(24)-a(25) from Giovanni Resta, Sep 21 2017
a(26) from Michael S. Branicky, Apr 25 2025
Showing 1-3 of 3 results.