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A191906
The remainder of (product of proper divisors of n) mod (sum of proper divisors of n).
6
0, 0, 2, 0, 0, 0, 1, 3, 2, 0, 0, 0, 4, 6, 4, 0, 9, 0, 4, 10, 8, 0, 0, 5, 10, 1, 0, 0, 36, 0, 1, 3, 14, 9, 41, 0, 16, 5, 0, 0, 0, 0, 16, 12, 20, 0, 44, 7, 6, 9, 36, 0, 54, 4, 0, 11, 26, 0, 0, 0, 28, 33, 8, 8, 66, 0, 42, 15, 10, 0, 81, 0, 34, 39, 16, 1, 72, 0, 10, 9, 38, 0, 84, 16, 40, 21
OFFSET
2,3
FORMULA
a(n) = A007956(n) mod A001065(n).
EXAMPLE
a(2) = 1 mod 1 = 0;
a(3) = 1 mod 1 = 0;
a(4) = 2 mod 3 = 2.
MAPLE
A007956 := n -> mul(i, i=op(numtheory[divisors](n) minus {1, n}));
A001065 := proc(n) numtheory[sigma](n)-n ; end proc:
A191906 := proc(n) A007956(n) mod A001065(n) ; end proc:
seq(A191906(n), n=2..90) ; # R. J. Mathar, Jun 25 2011
MATHEMATICA
Table[With[{pd=Most[Divisors[n]]}, Mod[Times@@pd, Total[pd]]], {n, 2, 90}] (* Harvey P. Dale, Nov 24 2021 *)
PROG
(PARI) A191906(n) = { my(m=1, s=0); fordiv(n, d, if(d<n, m *= d; s += d)); (m%s); }; \\ Antti Karttunen, Jul 11 2019
CROSSREFS
KEYWORD
nonn,look
AUTHOR
STATUS
approved