A246347 Record values in A135141.

1, 2, 4, 8, 9, 17, 19, 35, 39, 71, 79, 143, 159, 287, 319, 575, 639, 1151, 1279, 2303, 2559, 4607, 5119, 9215, 10239, 18431, 20479, 36863, 40959, 73727, 81919, 147455, 163839, 294911, 327679, 589823, 655359, 1179647, 1310719, 2359295, 2621439, 4718591, 5242879, 9437183, 10485759

Offset

1,2

Comments

In binary, the terms of the sequence seem to follow a simple pattern:

1 = a(1)

10 = a(2)

100 = a(3)

1000 = a(4)

1001 = a(5)

10001 = a(6)

10011 = a(7)

100011 = a(8)

100111 = a(9)

1000111 = a(10)

1001111 = a(11)

10001111 = a(12)

10011111 = a(13)

100011111 = a(14)

100111111 = a(15)

...

thus the sequence seems to consist of, after 1 and 2, an interleaving of sequence A153894: 4, 9, 19, 39, 79, 159, 319, ... with the sequence A052996 from its third term onward: 8, 17, 35, 71, 143, ...

Links

Antti Karttunen, Table of n, a(n) for n = 1..112

Formula

a(n) = A135141(A246346(n)).

Mathematica

Union[FromDigits[#, 2]&/@Flatten[Table[{PadRight[{1, 0, 0}, n, 1], PadRight[ {1, 0, 0, 0}, n, 1]}, {n, 30}], 1]] (* Harvey P. Dale, May 03 2015 *)

Prog

(PARI) \\ See code in A246348.
(Scheme) (define (A246347 n) (A135141 (A246346 n)))

Crossrefs

A246346 gives the corresponding positions in A135141.

Cf. A052996, A153894, A246348, A246360.

Sequence in context: A111261 A276773 A294441 * A255717 A354973 A177404

Adjacent sequences: A246344 A246345 A246346 * A246348 A246349 A246350

Keyword

nonn

Author

Antti Karttunen, Aug 27 2014 after Robert G. Wilson v's note in A135141

Status

approved