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A176083 a(n) = 2^(2n-2) mod prime(2n). 1
1, 4, 3, 7, 24, 25, 11, 7, 22, 12, 9, 1, 5, 69, 1, 62, 41, 16, 133, 89, 39, 3, 162, 66, 121, 12, 4, 109, 163, 85, 135, 52, 251, 8, 14, 6, 154, 126, 167, 284, 149, 158, 254, 110, 318, 23, 75, 23, 59, 279, 478, 513, 290, 58, 256, 345, 347, 25, 58, 361, 672, 681, 673, 697, 669, 609, 278, 739, 355, 529, 543, 478 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = 2^(2n-2) mod A000040(2n).

EXAMPLE

a(20)=89 because (2^(2*20-2) mod prime(2*20))=(274877906944 mod 173)=89.

MAPLE

A176083 := proc(n) modp(2^(2*n-2) , ithprime(2*n)) ; end proc:

MATHEMATICA

Table[PowerMod[4, n-1, Prime[2*n]], {n, 100}] (* G. C. Greubel, Nov 27 2019 *)

PROG

(Sage) A176083 = lambda n: (2**(2*n-2)) % nth_prime(2*n) # D. S. McNeil, Dec 07 2010

(PARI) vector(100, n, lift(Mod(4, prime(2*n))^(n-1)) ) \\ G. C. Greubel, Nov 27 2019

(MAGMA) [Modexp(4, n-1, NthPrime(2*n)): n in [1..100]]; // G. C. Greubel, Nov 27 2019

CROSSREFS

Cf. A000079, A175803.

Sequence in context: A228949 A048227 A213661 * A092193 A277117 A155910

Adjacent sequences:  A176080 A176081 A176082 * A176084 A176085 A176086

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Dec 07 2010

EXTENSIONS

Corrected and extended by D. S. McNeil, Dec 07 2010

Terms a(50) onward added by G. C. Greubel, Nov 27 2019

STATUS

approved

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Last modified July 5 17:29 EDT 2020. Contains 335473 sequences. (Running on oeis4.)