The On-Line Encyclopedia of Integer Sequences (OEIS)

A320985 revision #29

A320985

Complement of A092855.

1, 4, 6, 8, 9, 10, 11, 12, 14, 15, 20, 21, 24, 25, 28, 29, 37, 38, 42, 47, 48, 51, 52, 54, 55, 57, 58, 59, 60, 62, 63, 64, 66, 69, 70, 72, 78, 81, 82, 83, 85, 86, 89, 92, 93, 96, 100, 102, 104, 106, 107, 109, 111, 113, 119, 121, 122, 128, 129, 130, 134, 136, 139

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OFFSET

1,2

COMMENTS

Positions of 0 in the binary expansion of sqrt(2) after the radix point. With a prepended 0, A092855 gives the positions of 1.

LINKS

Table of n, a(n) for n=1..63.

Paolo Xausa, Table of n, a(n) for n = 1..10000

EXAMPLE

In binary, sqrt(2) is read as 1.0110101000001001111001... The 1st, 4th, 6th and 8th digits after the radix are 0's, so the first four terms are 1, 4, 6 and 8.

MATHEMATICA

PositionIndex[First[RealDigits[Sqrt[2], 2, 200]]][0] - 1 (* Paolo Xausa, Aug 27 2024 *)

PROG

(PARI) default(realprecision, 150); x=sqrt(2); for(n=1, 150, if(!(floor(x*2^n)%2), print1(n, ", ")))

(PARI) Vec(select(x->(x==0), binary(sqrt(2))[2], 1)) \\ Michel Marcus, Oct 29 2018

CROSSREFS

Cf. A004539, A092855.

Sequence in context: A365471 A228651 A045762 * A047748 A299540 A085558

Adjacent sequences: A320982 A320983 A320984 * A320986 A320987 A320988

KEYWORD

nonn,base

AUTHOR

Jianing Song, Oct 27 2018

STATUS

reviewed