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.

A155592 8^n+2^n-1^n.

Original entry on oeis.org

1, 9, 67, 519, 4111, 32799, 262207, 2097279, 16777471, 134218239, 1073742847, 8589936639, 68719480831, 549755822079, 4398046527487, 35184372121599, 281474976776191, 2251799813816319, 18014398509744127, 144115188076380159
Offset: 0

Views

Author

Mohammad K. Azarian, Jan 24 2009

Keywords

Crossrefs

Programs

  • Mathematica
    Table[8^n+2^n-1^n,{n,0,30}] (* or *) LinearRecurrence[{11,-26,16},{1,9,67},30] (* Harvey P. Dale, Jul 09 2017 *)
  • PARI
    a(n)=8^n+2^n-1 \\ Charles R Greathouse IV, Jun 11 2015

Formula

G.f.: 1/(1-8*x)+1/(1-2*x)-1/(1-x). E.g.f.: e^(8*x)+e^(2*x)-e^x.
a(n)=10*a(n-1)-16*a(n-2)-7 with a(0)=1, a(1)=9 - Vincenzo Librandi, Jul 21 2010
a(n) = A074603(n)-1. - R. J. Mathar, Mar 10 2022

A081342 a(n) = (8^n + 2^n)/2.

Original entry on oeis.org

1, 5, 34, 260, 2056, 16400, 131104, 1048640, 8388736, 67109120, 536871424, 4294968320, 34359740416, 274877911040, 2199023263744, 17592186060800, 140737488388096, 1125899906908160, 9007199254872064, 72057594038190080, 576460752303947776, 4611686018428436480
Offset: 0

Views

Author

Paul Barry, Mar 18 2003

Keywords

Comments

Binomial transform of A034494.
5th binomial transform of {1, 0, 9, 0, 81, 0, 729, 0, ...}.

Crossrefs

Programs

Formula

a(n) = (8^n + 2^n)/2.
a(n) = 10*a(n-1) - 16*a(n-2), a(0)=1, a(1)=5.
G.f.: (1-5*x)/((1-2*x)*(1-8*x)).
E.g.f.: exp(5*x)*cosh(3*x).
a(n) = ((5+sqrt(9))^n + (5-sqrt(9))^n)/2. - Al Hakanson (hawkuu(AT)gmail.com), Dec 08 2008
a(n) = A074603(n)/2. - Michel Marcus, Jan 09 2020

A045581 Numbers k that divide 8^k + 2^k.

Original entry on oeis.org

1, 2, 4, 5, 8, 16, 25, 32, 34, 64, 125, 128, 205, 256, 512, 578, 625, 1024, 1025, 1028, 2048, 2525, 3125, 4096, 5125, 8192, 8405, 9826, 10256, 12625, 15625, 16384, 25625, 32768, 42025, 63125, 65536, 78125, 103525, 128125, 131072, 167042, 168305
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A074603.

Programs

  • Mathematica
    Select[Range[200000], Divisible[PowerMod[2, #, #] + PowerMod[8, #, #], #] &] (* Amiram Eldar, Oct 23 2021 *)
Showing 1-3 of 3 results.