A122159 - OEIS

A122159

Period of A002067 modulo prime(n).

1, 1, 8, 3, 10, 24, 32, 18, 22, 56, 30, 72, 80, 42, 23, 104, 29, 120, 66, 70, 144, 39, 41, 176, 192, 200, 51, 53, 216, 224, 63, 130, 272, 69, 296, 150, 312, 162, 166, 344, 178, 360, 95, 384, 392, 99, 105, 222, 226, 456, 464, 238, 480, 125, 512, 131, 536, 270, 552

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OFFSET

1,3

LINKS

Table of n, a(n) for n=1..59.

FORMULA

a(n) = A122149(A000040(n)).

EXAMPLE

A002067 modulo 5 is 1, 1, 2, 2, 4, 4, 3, 3, 1, 1, 2, 2, 4, 4, 3, 3, 1, 1, ... with period 8.

MATHEMATICA

max = 100; se = Series[InverseErf[2*x/Sqrt[Pi]], {x, 0, 2*max + 1}]; a[n_] := (2 n + 1)!/2^n*Coefficient[se, x, 2*n + 1]; A002067 = Table[a[n], {n, 0, max}]; period[lst_List] := Catch[lg = If[Length[lst] <= 5, 2, 5]; lst1 = lst[[1 ;; lg]]; km = Length[lst] - lg; Do[If[lst1 == lst[[k ;; k + lg - 1]], Throw[k - 1]]; If[k == km, Throw[0]], {k, 2, km}]]; Table[ period[Mod[A002067, Prime[n]] // Reverse] , {n, 1, 15}] (* Jean-François Alcover, Dec 17 2012 *)

CROSSREFS

Cf. A002067, A122149.

Sequence in context: A246671 A069610 A257811 * A365445 A069200 A069218

Adjacent sequences: A122156 A122157 A122158 * A122160 A122161 A122162

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Aug 06 2008

EXTENSIONS

a(9)-a(15) from Jean-François Alcover, Dec 17 2012

More terms from Jinyuan Wang, Jul 30 2022

STATUS

approved