A065187 "Greedy Dragons" permutation of the natural numbers, inverse of A065186.

1, 4, 2, 5, 3, 6, 9, 7, 10, 8, 11, 14, 12, 15, 13, 16, 19, 17, 20, 18, 21, 24, 22, 25, 23, 26, 29, 27, 30, 28, 31, 34, 32, 35, 33, 36, 39, 37, 40, 38, 41, 44, 42, 45, 43, 46, 49, 47, 50, 48, 51, 54, 52, 55, 53, 56, 59, 57, 60, 58, 61, 64, 62, 65, 63, 66, 69, 67, 70, 68, 71, 74

Offset: 1

Author

Antti Karttunen, Oct 19 2001

Keywords

• nonn

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..10000
• Index entries for sequences that are permutations of the natural numbers

Programs

Mathematica

Rest@ CoefficientList[Series[x (2 x^5 - 2 x^4 + 3 x^3 - 2 x^2 + 3 x + 1)/((x - 1) (x^5 - 1)), {x, 0, 72}], x] (* Michael De Vlieger, Oct 23 2017 *)

Formula

From Chai Wah Wu, Oct 23 2017: (Start)

a(1) = 1, a(2) = 4, a(3) = 2, a(4) = 5, a(5) = 3; for n > 5, a(n) = a(n-5) + 5.

a(n) = a(n-1) + a(n-5) - a(n-6) for n > 6.

G.f.: x*(2*x^5 - 2*x^4 + 3*x^3 - 2*x^2 + 3*x + 1)/((x - 1)*(x^5 - 1)). (End)