

A213861


First occurrence of n in A213859.


1



2, 0, 1, 3, 4, 2949, 8, 11, 12, 15, 17, 115, 20, 7863275, 24, 27, 16, 73, 32, 35, 25, 39, 33, 103, 38, 48589961800007, 228, 51, 119, 97, 56, 59, 47, 323, 52, 581, 69, 71, 43, 2277, 77, 17509, 80, 75, 84, 87, 68, 133, 92, 95, 2209, 99, 53, 29363, 104, 107, 6848, 111, 2585, 3241, 116, 449, 120, 7847, 78, 1111, 129, 173, 132, 135, 137, 5340185
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,1


LINKS

Table of n, a(n) for n=0..71.


FORMULA

a(n) = smallest k>n such that 2^k == n (mod k+2).


EXAMPLE

Smallest n such that A213859(n) = 7 is 11, so a(7) = 11.


MATHEMATICA

nn = 25; t = Table[1, {nn}]; Do[p = PowerMod[2, n, n + 2]; If[0 <= p <= nn && t[[p + 1]] == 1, t[[p + 1]] = n], {n, 0, 10^7}]; t (* T. D. Noe, Jun 26 2012 *)


CROSSREFS

Cf. A213859, A213407, A036236
Sequence in context: A134405 A091612 A253672 * A108458 A254281 A295682
Adjacent sequences: A213858 A213859 A213860 * A213862 A213863 A213864


KEYWORD

nonn


AUTHOR

Alex Ratushnyak, Jun 22 2012


EXTENSIONS

a(26)a(50) from T. D. Noe, Jun 26 2012
Terms a(25) and a(51) onward from Max Alekseyev, Feb 01 2014


STATUS

approved



