A065166 Permutation t->t+3 of Z, folded to N.
6, 8, 4, 10, 2, 12, 1, 14, 3, 16, 5, 18, 7, 20, 9, 22, 11, 24, 13, 26, 15, 28, 17, 30, 19, 32, 21, 34, 23, 36, 25, 38, 27, 40, 29, 42, 31, 44, 33, 46, 35, 48, 37, 50, 39, 52, 41, 54, 43, 56, 45, 58, 47, 60, 49, 62, 51, 64, 53, 66, 55, 68, 57, 70, 59, 72, 61, 74, 63, 76, 65, 78
Offset: 1
Keywords
Links
- Joe Buhler and R. L. Graham, Juggling Drops and Descents, Amer. Math. Monthly, 101, (no. 6) 1994, 507 - 519.
- Index entries for sequences that are permutations of the natural numbers
Formula
Let f: Z -> N be given by f(z) = 2z if z>0 else 2|z|+1, with inverse g(z) = z/2 if z even else (1-z)/2. Then a(n) = f(g(n)+3).
Empirical g.f.: x*(3*x^7-3*x^6+4*x^5-4*x^4+4*x^3-10*x^2+2*x+6) / ((x-1)^2*(x+1)). [Colin Barker, Feb 18 2013]
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