A185061 Position of the first occurrence of n in A193358 when it is considered to have the starting offset 1 instead of 0.

1, 2, 5, 3, 11, 7, 19, 13, 29, 21, 41, 31, 55, 43, 71, 57, 89, 73, 109, 91, 131, 111, 155, 133, 181, 157, 209, 183, 239, 211, 271, 241, 305, 273, 341, 307, 379, 343, 419, 381, 461, 421, 505, 463, 551, 507, 599, 553, 649, 601, 701, 651, 755, 703, 811, 757

Offset

1,2

Comments

Conjecture: Only odd numbers occur after 2. - Antti Karttunen, Jun 13 2013

Conjecture is true. - Chai Wah Wu, Jun 07 2016

Links

Table of n, a(n) for n=1..56.

Formula

a(n) = A193422(n)+1, or in other words, 1 + the position of the first occurrence of n in A193358. - Antti Karttunen, Jun 13 2013

From Chai Wah Wu, Jun 07 2016: (Start)

G.f.: x*(x^6 - x^5 - 3*x^4 + 4*x^3 - x^2 - x - 1)/((x - 1)^3*(x + 1)^2).

a(2*n) = n*(n-1) + 1 for n > 1.

a(2*n+1) = n*(n+3) + 1.

a(n) = a(n-1) + 2*a(n-2) - 2*a(n-3) - a(n-4) + a(n-5) for n > 7. (End)

Mathematica

aux[0]=1; aux[1]=2; aux[n_]:=aux[n]=aux[n-aux[n-2]]+2;
a[i_]:={n=0; While[!(aux[n]==i), n++]; n};
Flatten[Table[a[i]+1, {i, 1, 100}]]
(* corrected by Robert Price, Jun 06 2016 *)

Crossrefs

Cf. A193358.

Sequence in context: A178174 A094744 A229608 * A129198 A122442 A225258

Adjacent sequences: A185058 A185059 A185060 * A185062 A185063 A185064

Keyword

nonn,easy

Author

José María Grau Ribas, Jan 22 2012

Extensions

Description clarified to take heed of changed offset of A193358 by Antti Karttunen, Jun 13 2013

Status

approved