A114645 The numbers 2^n-1 written in groups of three digits, with leading zeros omitted.

137, 153, 163, 127, 255, 511, 102, 320, 474, 95, 819, 116, 383, 327, 676, 553, 513, 107, 126, 214, 352, 428, 710, 485, 752, 97, 151, 419, 430, 383, 886, 71, 677, 721, 533, 554, 431, 671, 88, 631, 342, 177, 272, 684, 354, 555, 368, 709, 111, 73, 741, 823, 214, 748

Offset: 1

Author

N. J. A. Sloane, Feb 18 2006

Keywords

• nonn
• base
• dumb

Examples

			1,3,7,15,31,63,...
		

References

• Heard over coffee at the Computers in Scientific Discovery meeting in Ghent, Feb 02 2006.

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..10000

Programs

Mathematica

FromDigits[#] & /@ Partition[ Flatten[ IntegerDigits[ Table[ 2^n - 1, {n, 31}]]], 3] (* Robert G. Wilson v, Jun 23 2014 *)

Python

from itertools import count, islice
def bgen(): yield from (d for n in count(1) for d in str((1 << n)-1))
def agen(): g = bgen(); yield from (int("".join(t)) for t in zip(g, g, g))
print(list(islice(agen(), 54))) # Michael S. Branicky, Dec 25 2022

Extensions

More terms from Matthew Conroy, Mar 12 2006