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A153055

Numbers k such that the binary expansion of k is a substring of the binary expansion of 1/k.

11, 13, 27, 29, 45, 53, 54, 59, 61, 79, 83, 101, 103, 106, 107, 109, 115, 121, 125, 139, 149, 155, 158, 163, 166, 169, 173, 181, 187, 197, 199, 202, 206, 211, 212, 213, 218, 227, 235, 237, 251, 293, 298, 310, 311, 319, 326, 329, 345, 346, 349, 353, 361, 362, 369

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..55.

EXAMPLE

13 is a term because bin(13) = 1101 and bin(1/13) = .000100111011... (repeats infinitely) and 1101 appears in the binary expansion of the reciprocal.

PROG

(Python)

def isok(k):

s=bin(k)[2:]

digits=k+len(s)