A209247 a(n) = b(b(n-1)) + b(b((abs(n - b(b(n - 2))) - 1)) where b(n) = A188163(n).

1, 23, 33, 40, 61, 62, 65, 80, 115, 116, 117, 120, 125, 128, 141, 199, 228, 229, 230, 231, 234, 237, 238, 241, 246, 249, 264, 286, 289, 304, 370, 403, 449, 450, 451, 452, 453, 456, 459, 460, 461, 464, 469, 470, 473, 483, 486, 496, 518, 519, 522, 527, 530, 543

Offset

2,2

Comments

The resulting sequence has a Cantor staircase effect, but is not really a recursion since the values are read from tables of the type A004001 and A188163. The idea for the sequence was based on a version of A087873 suggested by an email.

The number of opening and closing parenthesis in NAME don't match, so it remains dubious how a(n) is defined. - R. J. Mathar, Mar 11 2024

The NAME is misleading. Following the Mma code this seems to be derived from A371555. - R. J. Mathar, Mar 27 2024

Links

Table of n, a(n) for n=2..55.

Mathematica

Clear[q0, q1, p, n, m, a, b]
(* define an A004001-like sequence and table*)
q0[0] = 1; q0[1] = 1;
q0[2] = 1;
q0[n_Integer] := q0[n] = q0[q0[n - 1]] + q0[n - q0[n - 1]];
a = Table[q0[n], {n, 0, 500}];
(* define an A188163-like table from the preceding table*)
p[n_] := Flatten[Table[If[a[[m]] == n, m, {}], {m, 1, Length[a]}]][[1]]
Table[p[n], {n, 1, Floor[Length[a]/2]}]
(* dual function of function table*)
b = Table[p[p[n - 1]], {n, 2, Floor[Length[a]/4]}]
q1[0] = 1; q1[1] = 1; q1[2] = 1;
(* build sequence from table values*)
q1[n_Integer] := q1[n] = b[[n]] + b[[Abs[n - b[[n - 1]]]]]
c = Table[q1[n], {n, 2, Floor[Length[a]/9]}]

Crossrefs

Cf. A087873, A188163, A004001.

Sequence in context: A044013 A081991 A118298 * A076091 A107074 A264101

Adjacent sequences: A209244 A209245 A209246 * A209248 A209249 A209250

Keyword

nonn,uned

Author

Roger L. Bagula, Jan 13 2013

Status

approved