A114807 The numbers 4^n-1 written in groups of three digits, with leading zeros omitted.
315, 632, 551, 23, 409, 516, 383, 655, 352, 621, 431, 48, 575, 419, 430, 316, 777, 215, 671, 88, 632, 684, 354, 551, 73, 741, 823, 429, 496, 729, 517, 179, 869, 183, 687, 194, 767, 352, 748, 779, 69, 431, 99, 511, 627, 775, 439, 804, 651, 110, 317, 592, 186, 44
Offset: 1
Examples
3, 15, 63, 255, 1023, 4095, 16383, ...
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..1000
Programs
-
Mathematica
FromDigits[#] & /@ Partition[ Flatten@ IntegerDigits@ Table[4^n - 1, {n, 22}], 3] (* Robert G. Wilson v, Jun 23 2014 *) FromDigits/@Partition[Flatten[IntegerDigits/@(4^Range[30]-1)],3] (* Harvey P. Dale, Jun 03 2025 *) -
Python
from itertools import count, islice def bgen(): yield from (d for n in count(1) for d in str((1 << 2*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
a(4) and following changed by Georg Fischer, Dec 25 2022