

A145641


Numbers whose binary representation is the concatenation of n 1's, n 0's and n 1's.


4



5, 51, 455, 3855, 31775, 258111, 2080895, 16711935, 133956095, 1072694271, 8585742335, 68702703615, 549688713215, 4397778092031, 35183298379775, 281470681808895, 2251782633947135, 18014329790267391, 144114913198473215, 1152920405096267775, 9223367638810361855
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OFFSET

1,1


COMMENTS

Numbers whose binary representation are the members of A138721.


LINKS

Table of n, a(n) for n=1..21.
Index entries for linear recurrences with constant coefficients, signature (15,70,120,64).


FORMULA

G.f.: x*(40*x^224*x+5)/((x1)*(2*x1)*(4*x1)*(8*x1)).  Colin Barker, Nov 04 2012
a(n) = (2^n1)*(2^(2*n)+1) = 8^n  4^n + 2^n  1.  Alois P. Heinz, Nov 04 2012


MAPLE

a:= n> 8^n4^n+2^n1:
seq(a(n), n=1..30); # Alois P. Heinz, Nov 04 2012


CROSSREFS

Cf. A138721.
Sequence in context: A068540 A208997 A041043 * A317782 A195211 A106415
Adjacent sequences: A145638 A145639 A145640 * A145642 A145643 A145644


KEYWORD

easy,nonn,base


AUTHOR

Omar E. Pol, Oct 14 2008


EXTENSIONS

More terms from Colin Barker, Nov 04 2012


STATUS

approved



