|
|
A308721
|
|
Locations of the first occurrence of pair (0,n) in the van Eck sequence (A181391).
|
|
2
|
|
|
0, 1, 3, 20, 24, 10, 30, 276, 388, 81, 225, 726, 2935, 1408, 7718, 5624, 5680, 85998, 26706, 546290, 1112929, 702575, 3425417, 10537360, 21301906, 217230900, 108698091, 32381774, 846522986, 851764846, 11692311325, 46163898987
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
COMMENTS
|
a(33) = 118456929919 and a(34) = 250327022558 but we do not yet know a(32).
|
|
LINKS
|
|
|
EXAMPLE
|
For a(5)=10, the pair (0,5) first occurs in A181391 at element 10.
|
|
MATHEMATICA
|
With[{s = Nest[# /. {{Longest[p___], a_, q___, a_} :> {p, a, q, a, Length[{a, q}]}, {a___} :> {a, 0}} &, {}, 10^3]}, TakeWhile[#, # > -1 &] &@ Array[If[Length@ # == 0, -1, #[[1, 1]] - 1 ] &@ SequencePosition[s, {0, #}] &, Max@ s, 0]] (* Michael De Vlieger, Jul 08 2019, after JungHwan Min at A181391 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
sign,more
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|