A131793 3 odds, 3 evens.

1, 3, 5, 2, 4, 6, 7, 9, 11, 8, 10, 12, 13, 15, 17, 14, 16, 18, 19, 21, 23, 20, 22, 24, 25, 27, 29, 26, 28, 30, 31, 33, 35, 32, 34, 36, 37, 39, 41, 38, 40, 42, 43, 45, 47, 44, 46, 48, 49, 51, 53, 50, 52, 54, 55, 57, 59, 56, 58, 60, 61, 63, 65, 62, 64, 66, 67, 69, 71, 68, 70, 72

Offset

1,2

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,1,-1).

Index entries for sequences that are permutations of the natural numbers.

Formula

a(n) = 2*(3*floor((n-1)/6)+((n-1) mod 3)+1)-(floor((n+2)/3) mod 2). - Joshua Zucker, Aug 29 2012

G.f.: x*(1 + 2*x + 2*x^2 - 3*x^3 + 2*x^4 + 2*x^5)/(1 - x - x^6 + x^7). - Robert Israel, May 10 2020

Sum_{n>=1} (-1)^(n+1)/a(n) = log(2)/3 + log(3)/2 - Pi/(6*sqrt(3)). - Amiram Eldar, Feb 09 2023

Maple

f:= gfun:-rectoproc({a(n) = a(n-1)+a(n-6)-a(n-7), a(1)=1, a(2)=3, a(3)=5, a(4)=2, a(5)=4, a(6)=6, a(7)=7}, a(n), remember):
map(f, [$1..100]); # Robert Israel, May 10 2020

Mathematica

LinearRecurrence[{1, 0, 0, 0, 0, 1, -1}, {1, 3, 5, 2, 4, 6, 7}, 100] (* Amiram Eldar, Feb 09 2023 *)

Crossrefs

Cf. A271833.

Sequence in context: A222601 A104807 A309492 * A065186 A210521 A219249

Adjacent sequences: A131790 A131791 A131792 * A131794 A131795 A131796

Keyword

nonn

Author

Paul Curtz, Oct 23 2007

Status

approved