

A171912


Van Eck sequence (cf. A181391) starting with 2.


1



2, 0, 0, 1, 0, 2, 5, 0, 3, 0, 2, 5, 5, 1, 10, 0, 6, 0, 2, 8, 0, 3, 13, 0, 3, 3, 1, 13, 5, 16, 0, 7, 0, 2, 15, 0, 3, 11, 0, 3, 3, 1, 15, 8, 24, 0, 7, 15, 5, 20, 0, 5, 3, 12, 0, 4, 0, 2, 24, 14, 0, 4, 6, 46, 0, 4, 4, 1, 26, 0, 5, 19, 0, 3, 21, 0, 3, 3, 1, 11, 42, 0, 6, 20, 34, 0, 4, 20, 4
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OFFSET

1,1


COMMENTS

A van Eck sequence is defined recursively by a(n+1) = min { k > 0  a(nk) = a(n) } or 0 if this set is empty.  M. F. Hasler, Jun 12 2019


LINKS

Table of n, a(n) for n=1..89.


MATHEMATICA

t = {2};
Do[
d = Quiet[Check[Position[t, Last[t]][[2]][[1]], 0]];
If[d == 0, x = 0, x = Length[t]  d];
AppendTo[t, x], 100]
t (* Horst H. Manninger, Aug 30 2020 *)


PROG

(PARI) A171912_vec(N, a=2, i=Map())={vector(N, n, a=if(n>1, iferr(nmapget(i, a), E, 0)+mapput(i, a, n), a))} \\ M. F. Hasler, Jun 11 2019


CROSSREFS

Cf. A181391, A171911, ..., A171918 (same but starting with 0, 1, ..., 8).
Sequence in context: A065293 A164615 A182034 * A306605 A054876 A109502
Adjacent sequences: A171909 A171910 A171911 * A171913 A171914 A171915


KEYWORD

nonn,changed


AUTHOR

N. J. A. Sloane, Oct 22 2010


EXTENSIONS

Name edited and crossreferences added by M. F. Hasler, Jun 12 2019


STATUS

approved



