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 1-2 of 2 results.

A321133 a(n) = 3*a(n-1) + 10*a(n-2), n >= 2; a(0)=-1, a(1)=23.

Original entry on oeis.org

-1, 23, 59, 407, 1811, 9503, 46619, 234887, 1170851, 5861423, 29292779, 146492567, 732405491, 3662142143, 18310481339, 91552865447, 457763409731, 2288818883663, 11444090748299, 57220461081527, 286102290727571, 1430511482997983, 7152557356269659, 35762786898788807, 178813934259063011
Offset: 0

Views

Author

Seiichi Manyama, Aug 27 2019

Keywords

Links

Crossrefs

Cf. A053428, A224473 (trimorphic number), A320468, A320469.

Programs

  • Mathematica
    LinearRecurrence[{3,10},{-1,23},30] (* Harvey P. Dale, Mar 11 2023 *)
  • PARI
    {a(n) = 3*5^n-4*(-2)^n}
  • PARI
    N=40; x='x+O('x^N); Vec((-1+26*x)/((1-5*x)*(1+2*x)))

Formula

a(n) = 3*5^n - 4*(-2)^n.
G.f.: (-1+26*x)/((1-5*x)*(1+2*x)).
a(n) == 7*A320469(n)*A224473(n) mod 10^n.
a(n)*A224473(n) == 7*A320469(n) mod 10^n.

A320469 a(n) = 3*a(n-1) + 10*a(n-2), n >= 2; a(0)=1, a(1)=1.

Original entry on oeis.org

1, 1, 13, 49, 277, 1321, 6733, 33409, 167557, 836761, 4185853, 20925169, 104634037, 523153801, 2615801773, 13078943329, 65394847717, 326973976441, 1634870406493, 8174350983889, 40871757016597, 204358780888681, 1021793912832013, 5108969547382849, 25544847770468677
Offset: 0

Views

Author

Seiichi Manyama, Aug 27 2019

Keywords

Links

Crossrefs

Cf. A053428, A224473 (trimorphic number), A320468, A321133.

Programs

  • PARI
    {a(n) = (4*(-2)^n+3*5^n)/7}
  • PARI
    N=40; x='x+O('x^N); Vec((1-2*x)/((1-5*x)*(1+2*x)))

Formula

a(n) = (4*(-2)^n + 3*5^n)/7.
G.f.: (1-2*x)/((1-5*x)*(1+2*x)).
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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