A265027 - OEIS

A265027

First differences of A048701 divided by 6.

1, 1, 3, 2, 1, 2, 11, 4, 2, 4, 1, 4, 2, 4, 43, 8, 4, 8, 2, 8, 4, 8, 1, 8, 4, 8, 2, 8, 4, 8, 171, 16, 8, 16, 4, 16, 8, 16, 2, 16, 8, 16, 4, 16, 8, 16, 1, 16, 8, 16, 4, 16, 8, 16, 2, 16, 8, 16, 4, 16, 8, 16, 683, 32, 16, 32, 8, 32, 16, 32, 4, 32, 16, 32, 8, 32, 16, 32, 2, 32, 16, 32, 8, 32, 16, 32, 4, 32, 16, 32, 8

(list; graph; refs; listen; history; text; internal format)

OFFSET

2,3

COMMENTS

Indices n such that a(n) = 1 are equal to row sums of Lucas triangle. In other words, a(A042950(n)) = 1. Additionally, a(A070875(n)) = 2 and a(A123760(n)) = 4. - Altug Alkan, Dec 04 2015

LINKS

N. J. A. Sloane, Table of n, a(n) for n = 2..32767

FORMULA

a(n) = A265026(n) / 6, for n > 1. - Altug Alkan, Dec 03 2015

MATHEMATICA

Differences@ Select[Range@ 12000, Reverse@ # == # && EvenQ@ Length@ # &@ IntegerDigits[#, 2] &]/6 (* Michael De Vlieger, Dec 04 2015 *)

PROG

(PARI) a048701(n) = my(f); f = length(binary(n)) - 1; 2^(f+1)*n + sum(i=0, f, bittest(n, i) * 2^(f-i));

vector(100, n, (a048701(n+1) - a048701(n)) / 6) \\ Altug Alkan, Dec 03 2015

CROSSREFS

Cf. A042950, A048701, A070875, A123760, A265026.

Sequence in context: A274512 A175947 A085068 * A079587 A237881 A112745

Adjacent sequences: A265024 A265025 A265026 * A265028 A265029 A265030

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Nov 30 2015

STATUS

approved