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A138676 a(n) = prime(n)^7 mod prime(n-1). 10
1, 2, 3, 4, 7, 4, 9, 6, 3, 12, 6, 30, 5, 1, 4, 43, 10, 7, 36, 57, 54, 31, 60, 45, 88, 27, 7, 21, 34, 98, 1, 120, 128, 62, 128, 133, 5, 84, 44, 22, 128, 112, 128, 172, 128, 67, 210, 105, 128 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

COMMENTS

Related sequences type prime(n)^k mod prime(n-1) (k=1,2,3,4)

prime(n) mod prime(n-1) is given in A001223

prime(n)^2 mod prime(n-1) is given in A038702

prime(n)^3 mod prime(n-1) is given in A138672

prime(n)^4 mod prime(n-1) is given in A138673

prime(n)^5 mod prime(n-1) is given in A138674

prime(n)^6 mod prime(n-1) is given in A138675

prime(n)^7 mod prime(n-1) is given in A138676

prime(n)^8 mod prime(n-1) is given in A138677

prime(n)^9 mod prime(n-1) is given in A138678

prime(n)^10 mod prime(n-1) is given in A138679

prime(n)^11 mod prime(n-1) is given in A138680

prime(n)^12 mod prime(n-1) is given in A138681

a(n) = 128 if prime(n-1) and prime(n) are twin primes and prime(n-1)>128. - Robert Israel, Feb 12 2020

LINKS

Robert Israel, Table of n, a(n) for n = 2..10000

EXAMPLE

a(1)=1 because 3^7 = 1 mod 2

a(2)=2 because 5^7 = 2 mod 3

MAPLE

seq(ithprime(n)&^7 mod ithprime(n-1), n=2..100); # Robert Israel, Feb 12 2020

MATHEMATICA

Table[Mod[Prime[n]^7, Prime[n - 1]], {n, 2, 50}]

(* The following program is more efficient because it only generates each prime once, but it is less easy to understand: *)

PowerMod[Last[#], 7, First[#]]&/@Partition[Prime[Range[60]], 2, 1] (* Harvey P. Dale, Sep 02 2016 *)

PROG

(MAGMA) [NthPrime(n)^7 mod NthPrime(n-1): n in [2..50]];  // Bruno Berselli, May 23 2011

CROSSREFS

Cf. A001223, A038702, A138672, A138673, A138674, A138675, A138676, A138677, A138678, A138679, A138680, A138681.

Sequence in context: A021430 A297110 A267695 * A297111 A035532 A176535

Adjacent sequences:  A138673 A138674 A138675 * A138677 A138678 A138679

KEYWORD

nonn,look

AUTHOR

Artur Jasinski, Mar 26 2008

STATUS

approved

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Last modified June 6 01:51 EDT 2020. Contains 334858 sequences. (Running on oeis4.)