A338820 - OEIS

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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

(list; graph; refs; listen; history; text; internal format)

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);