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A338935 a(n) = Sum_{d|n} (d^2 mod n). 2
0, 1, 1, 1, 1, 8, 1, 5, 1, 10, 1, 18, 1, 12, 20, 5, 1, 23, 1, 26, 17, 16, 1, 58, 1, 18, 10, 42, 1, 70, 1, 21, 32, 22, 40, 39, 1, 24, 23, 90, 1, 106, 1, 54, 71, 28, 1, 98, 1, 55, 44, 34, 1, 104, 37, 106, 29, 34, 1, 240, 1, 36, 77, 21, 65, 160, 1, 38, 56, 200, 1, 175, 1, 42, 60, 78, 94, 154, 1, 146 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

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

EXAMPLE

a(6) = (1^2 mod 6) + (2^2 mod 6) + (3^2 mod 6) + (6^2 mod 6) = 1+4+3+0 = 8.

MAPLE

f:= n -> add(t^2 mod n, t = numtheory:-divisors(n)):

map(f, [$1..100]);

PROG

(PARI) a(n) = sumdiv(n, d, lift(Mod(d, n)^2)); \\ Michel Marcus, Nov 16 2020

CROSSREFS

Cf. A000430 (a(n)=1), A338930 (a(n) is prime).

Sequence in context: A280040 A202284 A231772 * A200120 A154861 A153495

Adjacent sequences:  A338932 A338933 A338934 * A338936 A338937 A338938

KEYWORD

nonn

AUTHOR

J. M. Bergot and Robert Israel, Nov 16 2020

STATUS

approved

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Last modified September 16 18:26 EDT 2021. Contains 347473 sequences. (Running on oeis4.)