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A147540 Numbers whose binary representation is the concatenation of 2n-1 digits 1, n digits 0 and 2n-1 digits 1. 4
5, 231, 7967, 260223, 8372735, 268306431, 8588894207, 274869551103, 8796026044415, 281474440364031, 9007194961870847, 288230341800361983, 9223371762010423295, 295147902980463788031, 9444732948147641253887 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) is the number whose binary representation is A138826(n).

LINKS

Table of n, a(n) for n=1..15.

FORMULA

From R. J. Mathar, Nov 09 2008: (Start)

a(n) = 2^(2n-1) - 1 + 2^(5n-2) - 2^(3n-1).

G.f.: x(5+6x-128x^2+768x^3) / ((1-4x)(1-x)(1-32x)(1-8x)). (End)

MATHEMATICA

Table[FromDigits[Join[Table[1, {2n - 1}], Table[0, {n}], Table[1, {2n - 1}]], 2], {n, 1, 15}] (* Stefan Steinerberger, Nov 11 2008 *)

CROSSREFS

Cf. A138826.

Sequence in context: A103732 A065757 A157776 * A187366 A176898 A274996

Adjacent sequences:  A147537 A147538 A147539 * A147541 A147542 A147543

KEYWORD

base,easy,nonn

AUTHOR

Omar E. Pol, Nov 06 2008

EXTENSIONS

More terms from R. J. Mathar and Stefan Steinerberger, Nov 11 2008

STATUS

approved

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Last modified October 19 01:25 EDT 2019. Contains 328211 sequences. (Running on oeis4.)