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

1,1

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

Example

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

Mathematica

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

Prog

(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

Crossrefs

Sequence in context: A138329 A066477 A139647 * A057879 A179912 A108382

Adjacent sequences: A114642 A114643 A114644 * A114646 A114647 A114648

Keyword

nonn,base,dumb

Author

N. J. A. Sloane, Feb 18 2006

Extensions

More terms from Matthew Conroy, Mar 12 2006

Status

approved