A340646 - OEIS

%I #10 Jan 21 2021 10:51:25

%S 2,4,6,3,7,16,5,9,7,1,6,16,21,32,36,16,17,22,63,4,10,75,63,96,1,38,2,

%T 66,109,100,82,119,57,53,119,67,141,137,116,89,103,85,187,101,74,58,

%U 146,144,216,37,238,16,4,21,254,185,216,187,43,15,123,109,69

%N a(n) = (prime(n)^n) mod prime(n+1).

%e a(1) = prime(1)^1 mod prime(1+1) = 2^1 mod 3 = 2 mod 3 = 2,

%e a(2) = prime(2)^2 mod prime(2+1) = 3^2 mod 5 = 9 mod 5 = 4,

%e a(3) = prime(3)^3 mod prime(3+1) = 5^3 mod 7 = 125 mod 7 = 6,

%e a(4) = prime(4)^4 mod prime(4+1) = 7^4 mod 11 = 2401 mod 11 = 3,

%e a(5) = prime(5)^5 mod prime(5+1) = 11^5 mod 13 = 161051 mod 13 = 7.

%o (Ruby) require 'prime'

%o values = []

%o primes = Prime.first(20)

%o primes.each_index do |n|

%o     next if n < 1

%o     values << (primes[n-1] ** n) % primes[n]

%o end

%o p values

%o (PARI) a(n)=my(p=prime(n)); lift(Mod(p, nextprime(p+1))^n); \\ _Michel Marcus_, Jan 14 2021

%Y Cf. A000040, A240546.

%K nonn

%O 1,1

%A _Simon Strandgaard_, Jan 14 2021