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.

A320468 a(n) = a(n-1) + 20*a(n-2), n >= 2; a(0)=1, a(1)=41.

Original entry on oeis.org

1, 41, 61, 881, 2101, 19721, 61741, 456161, 1690981, 10814201, 44633821, 260917841, 1153594261, 6371951081, 29443836301, 156882857921, 745759583941, 3883416742361, 18798608421181, 96466943268401, 472439111692021, 2401777977060041, 11850560210900461, 59886119752101281, 296897323970110501
Offset: 0

Views

Author

Seiichi Manyama, Aug 27 2019

Keywords

Links

Crossrefs

Cf. A053428, A224473 (trimorphic number), A320469, A321133.

Programs

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

Formula

a(n) = (-4)^(n+1) + 5^(n+1).
G.f.: (1+40*x)/((1-5*x)*(1+4*x)).
a(n) == 9*A053428(n)*A224473(n) mod 10^n.
a(n)*A224473(n) == 9*A053428(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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