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

Author

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

Keywords

• nonn

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

Crossrefs

A246346 gives the corresponding positions in A135141.

Cf. A052996, A153894, A246348, A246360.

Programs

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 *)

PARI

\\ See code in A246348.

Scheme

(define (A246347 n) (A135141 (A246346 n)))

Formula

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