A108906 First differences of A006899.

1, 1, 1, 4, 1, 7, 11, 5, 32, 17, 47, 115, 13, 256, 217, 295, 1024, 139, 1909, 2465, 1631, 8192, 3299, 13085, 26281, 6487, 65536, 46075, 84997, 262144, 7153, 517135, 545747, 502829, 2097152, 588665, 3605639, 5960299, 2428309, 16777216, 9492289

Offset: 1

Author

Ali A. Tanara (tanara(AT)khayam.ut.ac.ir), Jul 17 2005

Keywords

• easy
• nonn

Comments

In the 14th century Levi Ben Gerson proved that this sequence contains only four 1s; see A235365, A235366, A236210. - Jonathan Sondow, Jan 20 2014

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A006899.

Cf. also A235365, A235366, A236210.

Programs

Haskell

a108906 n = a108906_list !! (n-1)
a108906_list = zipWith (-) (tail a006899_list) a006899_list
-- Reinhard Zumkeller, Oct 09 2013

Maple

A:={seq(2^n,n=0..63)}: B:={seq(3^n,n=0..40)}: C:=sort(convert(A union B,list)): seq(C[j]-C[j-1],j=2..44); # Emeric Deutsch, Aug 03 2005

Mathematica

nn = 10^20; t = Union[ 2^Range[0, Floor[Log[2, nn]]], 3^Range[0, Floor[Log[3, nn]]]]; Differences@ t (* Robert G. Wilson v, May 26 2014 *)

Python

from sympy import integer_log
def A108906(n):
    m, m2 = 3**(n-1), 1<Chai Wah Wu, Oct 01 2024

Extensions

More terms from Emeric Deutsch, Aug 03 2005