A340646 a(n) = (prime(n)^n) mod prime(n+1).
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, 66, 109, 100, 82, 119, 57, 53, 119, 67, 141, 137, 116, 89, 103, 85, 187, 101, 74, 58, 146, 144, 216, 37, 238, 16, 4, 21, 254, 185, 216, 187, 43, 15, 123, 109, 69
Offset: 1
Keywords
Examples
a(1) = prime(1)^1 mod prime(1+1) = 2^1 mod 3 = 2 mod 3 = 2, a(2) = prime(2)^2 mod prime(2+1) = 3^2 mod 5 = 9 mod 5 = 4, a(3) = prime(3)^3 mod prime(3+1) = 5^3 mod 7 = 125 mod 7 = 6, a(4) = prime(4)^4 mod prime(4+1) = 7^4 mod 11 = 2401 mod 11 = 3, a(5) = prime(5)^5 mod prime(5+1) = 11^5 mod 13 = 161051 mod 13 = 7.
Programs
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PARI
a(n)=my(p=prime(n)); lift(Mod(p, nextprime(p+1))^n); \\ Michel Marcus, Jan 14 2021
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Ruby
require 'prime' values = [] primes = Prime.first(20) primes.each_index do |n| next if n < 1 values << (primes[n-1] ** n) % primes[n] end p values