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A038463

Sums of 12 distinct powers of 2.

4095, 6143, 7167, 7679, 7935, 8063, 8127, 8159, 8175, 8183, 8187, 8189, 8190, 10239, 11263, 11775, 12031, 12159, 12223, 12255, 12271, 12279, 12283, 12285, 12286, 13311, 13823, 14079, 14207, 14271, 14303, 14319, 14327, 14331, 14333

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OFFSET

1,1

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..10000

Robert Baillie, Summing the curious series of Kempner and Irwin, arXiv:0806.4410 [math.CA], 2008-2015. See p. 18 for Mathematica code irwinSums.m.

FORMULA

Sum_{n>=1} 1/a(n) = 1.386296350824871649202152615241744383837323713474767661902780220440945591424... (calculated using Baillie's irwinSums.m, see Links). - Amiram Eldar, Feb 14 2022

MATHEMATICA

Select[Range[15000], DigitCount[#, 2, 1] == 12 &] (* Amiram Eldar, Feb 14 2022 *)

PROG

(Python)

from itertools import islice

def A038463_gen(): # generator of terms

yield (n:=4095)

while True: yield (n:=n^((a:=-n&n+1)|(a>>1)) if n&1 else ((n&~(b:=n+(a:=n&-n)))>>a.bit_length())^b)

A038463_list = list(islice(A038463_gen(), 20)) # Chai Wah Wu, Mar 10 2025

CROSSREFS

Base 2 interpretation of A038454.