A338820 a(n) = Sum_{i=1..n-1} (prime(i)^2 mod prime(n)).

0, 1, 8, 10, 21, 39, 54, 58, 61, 135, 134, 213, 217, 259, 267, 449, 413, 530, 645, 471, 661, 734, 741, 1029, 1194, 1257, 1219, 1434, 1372, 1456, 1547, 1939, 2007, 1987, 2471, 2319, 2802, 2610, 2564, 3334, 3548, 3684, 3612, 3576, 4399, 3686, 5071, 4810, 4647, 5066, 6035, 5213, 5890, 6335, 6327

Offset

1,3

Comments

The sequence is not monotone, and not one-to-one: a(95)=a(97)=23038.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

The first three primes are 2, 3, 5, so a(3) = (2^2 mod 5) + (3^2 mod 5) = 4 + 4 = 8.

Maple

P:= [seq(ithprime(i), i=1..100)]:
seq(add(P[i]^2 mod P[n], i=1..n-1), n=1..100);

Prog

(PARI) a(n) = my(p=prime(n)); sum(i=1, n-1, lift(Mod(prime(i), p)^2)); \\ Michel Marcus, Nov 11 2020

Crossrefs

Cf. A338102, A338821.

Sequence in context: A300022 A346783 A073619 * A302429 A292999 A374111

Adjacent sequences: A338817 A338818 A338819 * A338821 A338822 A338823

Keyword

nonn

Author

J. M. Bergot and Robert Israel, Nov 10 2020

Status

approved