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A153825 Sum of proper divisors minus the number of proper divisors of n!. 2
0, 0, 0, 3, 29, 225, 1669, 14245, 118705, 1118001, 11705019, 144091717, 1738439017, 24817157329, 355309322689, 5378578597729, 86081749391905, 1570394279028289, 28281459220178401, 572031558109560385, 11458497230555053681 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
COMMENTS
a(n) is the sum of proper divisors minus the number of proper divisors of factorial number A000142(n).
LINKS
FORMULA
a(n) = A153824(n) - A153823(n) = A152770(A000142(n)).
MAPLE
with(numtheory): seq(sigma(factorial(n))-factorial(n)-tau(factorial(n))+1, n = 0 .. 22); # Emeric Deutsch, Jan 07 2009
MATHEMATICA
Table[DivisorSigma[1, n!]-n!-(DivisorSigma[0, n!]-1), {n, 0, 20}] (* Harvey P. Dale, Jan 14 2012 *)
PROG
(Magma) [DivisorSigma(1, Factorial(n)) - Factorial(n) - (DivisorSigma(0, Factorial(n))-1): n in [0..20]]; // Vincenzo Librandi, Aug 31 2016
(PARI) a(n) = (sigma(n!) - n!) - (numdiv(n!) - 1); \\ Michel Marcus, Aug 31 2016
CROSSREFS
Sequence in context: A083092 A174419 A220548 * A201490 A354402 A135163
KEYWORD
nonn
AUTHOR
Omar E. Pol, Jan 02 2009
EXTENSIONS
Extended by Emeric Deutsch, Jan 07 2009
STATUS
approved

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Last modified July 18 10:00 EDT 2024. Contains 374378 sequences. (Running on oeis4.)