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A066913 (sum of primes < n that do not divide n) (mod n). 1

%I #17 Aug 06 2019 20:34:06

%S 0,0,2,3,0,5,3,7,5,0,6,11,2,4,3,7,7,17,1,10,4,20,8,23,20,7,16,7,13,29,

%T 5,30,14,5,8,11,12,24,25,30,33,16,23,4,3,26,46,35,27,21,2,1,10,52,35,

%U 36,17,2,27,10,13,34,50,51,28,23,32,5,59,64,0,58,55,7,29,7,1,70,1

%N (sum of primes < n that do not divide n) (mod n).

%H Harvey P. Dale, <a href="/A066913/b066913.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = A066911(n) modulo n. - _Michel Marcus_, May 20 2014

%F a(prime(n)) = A071089(n). - _Michel Marcus_, May 20 2014

%e a(8) = (3 + 5 + 7) (mod 8) = 7 because 3, 5 and 7 are the primes < 8 that do not divide 8.

%t Table[Mod[Total[Select[Prime[Range[PrimePi[n]]],Mod[n,#]!=0&]],n],{n,80}] (* _Harvey P. Dale_, Aug 06 2019 *)

%o (PARI) a(n) = sum(i=1, n-1, if (isprime(i) && (n%i), i)) % n; \\ _Michel Marcus_, May 20 2014

%Y Cf. A066911, A071089.

%K nonn

%O 1,3

%A _Leroy Quet_, Jan 22 2002

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Last modified September 3 05:18 EDT 2024. Contains 375649 sequences. (Running on oeis4.)