A246705 Position of first n in A246694 (read as sequence with offset changed to 1); complement of A246706.
1, 3, 4, 6, 8, 10, 11, 13, 15, 17, 19, 21, 22, 24, 26, 28, 30, 32, 34, 36, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 106, 108, 110, 112, 114, 116, 118
Offset: 1
Examples
A246694 begins with 1, 1, 2, 3, 2, 4, 3, 5, 4, 6, 7, 5, 8, 6, 9, 7, so that, for a(n) = position of first n and b(n) = position of last n, we have a = (1,3,4,6,8,10,...) and b = (2,5,7,9,12,...). Note, however, that A246694 has offset 0, so the values here are off by 1 from the positions as given by the indices (b-file or list) in that sequence. - _M. F. Hasler_, Nov 17 2014
Programs
-
Mathematica
z = 25; t[0, 0] = 1; t[1, 0] = 1; t[1, 1] = 2; t[n_, 0] := If[OddQ[n], t[n - 1, n - 2] + 1, t[n - 1, n - 1] + 1]; t[n_, 1] := If[OddQ[n], t[n - 1, n - 1] + 1, t[n - 1, n - 2] + 1]; t[n_, k_] := t[n, k - 2] + 1; u = Flatten[Table[t[n, k], {n, 0, z}, {k, 0, n}]]; (*A246694*) w[n_] := Flatten[Position[u, n]]; A246705 = Table[First[w[n]], {n, 1, 3*z}]