A350493 - OEIS

%I #12 Jan 18 2022 21:48:50

%S 0,1,1,0,4,3,2,0,7,5,3,0,10,8,6,1,15,13,7,4,1,20,12,9,6,22,19,16,13,

%T 10,28,25,22,19,4,0,33,30,27,9,5,1,40,37,16,12,8,4,29,25,21,17,13,9,

%U 36,32,28,24,20,16,12,41,37,33,29,25,56,52,48,44,40,36

%N a(n) = floor(sqrt(prime(n)))^2 mod n.

%F a(n) = A065730(n) mod n.

%e a(4) = A065730(4) mod 4 =  4 mod 4 = 0;

%e a(5) = A065730(5) mod 5 =  9 mod 5 = 4;

%e a(6) = A065730(6) mod 6 =  9 mod 6 = 3;

%e a(7) = A065730(7) mod 7 = 16 mod 7 = 2.

%t Table[PowerMod[Floor[Sqrt[Prime[n]]],2,n],{n,72}] (* _Stefano Spezia_, Jan 02 2022 *)

%o (PARI) a(n) = (sqrtint(prime(n))^2) % n;

%o vector(20,n,a(n))

%o (Ruby) require 'prime'

%o values = []

%o Prime.first(20).each_with_index do |prime, i|

%o     values << ((Integer.sqrt(prime) ** 2) % (i + 1))

%o end

%o p values

%o (Python)

%o from sympy import prime, integer_nthroot

%o def a(n): return (integer_nthroot(prime(n), 2)[0]**2)%n

%o print([a(n) for n in range(1, 73)]) # _Michael S. Branicky_, Jan 02 2022

%Y Cf. A000040, A048760, A065730.

%K nonn

%O 1,5

%A _Simon Strandgaard_, Jan 01 2022