A350493 a(n) = floor(sqrt(prime(n)))^2 mod n.

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

Offset: 1

Author

Simon Strandgaard, Jan 01 2022

Keywords

• nonn

Examples

			a(4) = A065730(4) mod 4 =  4 mod 4 = 0;
a(5) = A065730(5) mod 5 =  9 mod 5 = 4;
a(6) = A065730(6) mod 6 =  9 mod 6 = 3;
a(7) = A065730(7) mod 7 = 16 mod 7 = 2.
		

Crossrefs

Cf. A000040, A048760, A065730.

Programs

Mathematica

Table[PowerMod[Floor[Sqrt[Prime[n]]],2,n],{n,72}] (* Stefano Spezia, Jan 02 2022 *)

PARI

a(n) = (sqrtint(prime(n))^2) % n;
vector(20,n,a(n))

Python

from sympy import prime, integer_nthroot
def a(n): return (integer_nthroot(prime(n), 2)[0]**2)%n
print([a(n) for n in range(1, 73)]) # Michael S. Branicky, Jan 02 2022

Ruby

require 'prime'
values = []
Prime.first(20).each_with_index do |prime, i|
    values << ((Integer.sqrt(prime) ** 2) % (i + 1))
end
p values

Formula

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