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.

A141060 Fourth quadrisection of Jacobsthal numbers A001045: a(n)=16a(n-1)-5.

Original entry on oeis.org

3, 43, 683, 10923, 174763, 2796203, 44739243, 715827883, 11453246123, 183251937963, 2932031007403, 46912496118443, 750599937895083, 12009599006321323, 192153584101141163, 3074457345618258603, 49191317529892137643
Offset: 0

Views

Author

Paul Curtz, Jul 30 2008

Keywords

Comments

Jacobsthal numbers ending with the decimal digit 3. - Jianing Song, Aug 30 2022

Crossrefs

The other quadrisections of A001045 are A195156 (first), A139792 (second), and A144864 (third).

Programs

Formula

a(n) = A139792(n) + A013776(n).
a(n+1) - a(n) = 10*A013709(n) = 40*A001025(n).
G.f.: (3-8*x)/((1-x)*(1-16*x)). [Colin Barker, Apr 05 2012]
a(0)=3, a(1)=43, a(n)=17*a(n-1)-16*a(n-2). - Harvey P. Dale, Mar 16 2015
From Jianing Song, Aug 30 2022: (Start)
a(n) = A001045(4*n+3).
a(n) = 10*A141032(n) + 3 = 20*A098704(n+1) + 1 = 40*A131865(n-1) + 1 for n >= 1. (End)

A334076 a(n) = bitwise NOR of n and 2n.

Original entry on oeis.org

0, 0, 1, 0, 3, 0, 1, 0, 7, 4, 1, 0, 3, 0, 1, 0, 15, 12, 9, 8, 3, 0, 1, 0, 7, 4, 1, 0, 3, 0, 1, 0, 31, 28, 25, 24, 19, 16, 17, 16, 7, 4, 1, 0, 3, 0, 1, 0, 15, 12, 9, 8, 3, 0, 1, 0, 7, 4, 1, 0, 3, 0, 1, 0, 63, 60, 57, 56, 51, 48, 49, 48, 39, 36, 33, 32, 35, 32, 33
Offset: 0

Views

Author

Alois P. Heinz, Apr 13 2020

Keywords

Comments

Exactly all bits that are 0 in both parameters (but not a leading 0 of both) are set to 1 in the output of bitwise NOR.

Crossrefs

Programs

  • Maple
    a:= n-> Bits[Nor](n, 2*n):
    seq(a(n), n=0..127);
  • PARI
    a(n) = my(x=bitor(n, 2*n)); bitneg(x, #binary(x)); \\ Michel Marcus, Apr 14 2020
  • Python
    def A334076(n):
        m = n|(2*n)
        return 0 if n == 0 else 2**(len(bin(m))-2)-1-m # Chai Wah Wu, Apr 14 2020
    

Formula

a(n) = 0 <=> n in { A247648 } union { 0 }.
a(n) = n-1 <=> n in { A000079 }.
a(n) = n/2 <=> n in { A125835 }.
a(n) = n*3/4 <=> n in { A141032 }.
Showing 1-2 of 2 results.