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

1,2


LINKS

Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for sequences that are permutations of the natural numbers
Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,1,1).


FORMULA

a(n) = (24*floor(n/6)+3*n^23*n+8+9*floor(n/3)*(3*floor(n/3)2*n+1)(3*n^27*n+8+3*floor(n/3)*(9*floor(n/3)6*n+7))*(1)^floor(n/3))/4.  Luce ETIENNE, Apr 08 2017
From Colin Barker, Apr 08 2017: (Start)
G.f.: x*(1 + x + 2*x^2  x^3 + 2*x^4 + x^5) / ((1  x)^2*(1 + x)*(1  x + x^2)*(1 + x + x^2)).
a(n) = a(n1) + a(n6)  a(n7) for n>7.
(End)


PROG

(PARI) Vec(x*(1 + x + 2*x^2  x^3 + 2*x^4 + x^5) / ((1  x)^2*(1 + x)*(1  x + x^2)*(1 + x + x^2)) + O(x^100)) \\ Colin Barker, Apr 08 2017


CROSSREFS

Sequence in context: A081725 A228083 A222234 * A274631 A275335 A056019
Adjacent sequences: A131039 A131040 A131041 * A131043 A131044 A131045


KEYWORD

nonn,easy


AUTHOR

Paul Curtz, Sep 23 2007


STATUS

approved

