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A178970 2^(2n-1) mod (2n+1). 4
2, 3, 4, 2, 6, 7, 2, 9, 10, 2, 12, 8, 20, 15, 16, 2, 22, 19, 2, 21, 22, 38, 24, 32, 2, 27, 52, 2, 30, 31, 2, 8, 34, 2, 36, 37, 17, 43, 40, 20, 42, 8, 2, 45, 32, 2, 27, 49, 29, 51, 52, 23, 54, 55, 2, 57, 77, 11, 15, 28, 2, 108, 64, 2, 66, 32, 47, 69, 70, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..70.

FORMULA

a(n) = A081294(n) mod A005408(n).

EXAMPLE

a(1)=(2^(2*1-1) mod (2*1+1))=(2^1 mod 3)=2.

MATHEMATICA

f[n_] := PowerMod[2, 2 n - 1, 2 n + 1]; Array[f, 70] (* Robert G. Wilson v, Jan 03 2011 *)

CROSSREFS

Cf. A000079.

Sequence in context: A152958 A278963 A308085 * A172054 A047994 A193024

Adjacent sequences:  A178967 A178968 A178969 * A178971 A178972 A178973

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Jan 03 2011

STATUS

approved

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Last modified May 25 02:01 EDT 2020. Contains 334581 sequences. (Running on oeis4.)