A153825 Sum of proper divisors minus the number of proper divisors of n!.
0, 0, 0, 3, 29, 225, 1669, 14245, 118705, 1118001, 11705019, 144091717, 1738439017, 24817157329, 355309322689, 5378578597729, 86081749391905, 1570394279028289, 28281459220178401, 572031558109560385, 11458497230555053681
Offset: 0
Keywords
Links
- G. C. Greubel, Table of n, a(n) for n = 0..500
Programs
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Magma
[DivisorSigma(1,Factorial(n)) - Factorial(n) - (DivisorSigma(0,Factorial(n))-1): n in [0..20]]; // Vincenzo Librandi, Aug 31 2016
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Maple
with(numtheory): seq(sigma(factorial(n))-factorial(n)-tau(factorial(n))+1, n = 0 .. 22); # Emeric Deutsch, Jan 07 2009
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Mathematica
Table[DivisorSigma[1,n!]-n!-(DivisorSigma[0,n!]-1),{n,0,20}] (* Harvey P. Dale, Jan 14 2012 *) -
PARI
a(n) = (sigma(n!) - n!) - (numdiv(n!) - 1); \\ Michel Marcus, Aug 31 2016
Extensions
Extended by Emeric Deutsch, Jan 07 2009
Comments