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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A142248 Odd numbers in A138123.

Original entry on oeis.org

1, 3, 7, 11, 17, 29, 47, 75, 123, 199, 321, 521, 843, 1363, 2207, 3571, 5777, 9349, 15127, 24475, 39603, 64079, 103681, 167761, 271443, 439203, 710647, 1149851, 1860497, 3010349, 4870847, 7881195, 12752043, 20633239, 33385281, 54018521, 87403803, 141422323, 228826127, 370248451
Offset: 1

Views

Author

Paul Curtz, Sep 18 2008

Keywords

Crossrefs

Cf. A000204, A138123.

Programs

  • PARI
    L(n) = fibonacci(n+1)+fibonacci(n-1); \\ A000204
T(n, k) = if (kA138123
lista(nn) = my(list = List()); for (k=1, nn, my(i=k, j=1, s=0); for (m=1, k, s += T(i,j); i--; j++;); if ((s>0) && (s%2), listput(list, s));); Set(list);

Formula

Conjectures from Chai Wah Wu, Apr 15 2024: (Start)
a(n) = a(n-1) + a(n-2) + a(n-3) - a(n-4) - a(n-5) for n > 6.
G.f.: x*(-2*x^5 - 3*x^4 + 3*x^2 + 2*x + 1)/((x - 1)*(x^2 + x - 1)*(x^2 + x + 1)). (End)

Extensions

Edited by N. J. A. Sloane, Dec 10 2008
More terms from Michel Marcus, Apr 16 2024
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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