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A154896 Sum of proper divisors minus the number of proper divisors of the perfect number A000396(n). 1
3, 23, 487, 8115, 33550311, 8589869023, 137438691291, 2305843008139952067, 2658455991569831744654692615953842055, 191561942608236107294793378084303638130997321548169039 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

a(n) is also the difference between the n-th perfect number and its number of proper divisors.

FORMULA

a(n) = A152770(A000396(n)) = A000396(n)-A133033(n).

EXAMPLE

a(2) is 23 because the second perfect number is 28 and the sum of proper divisors of 28 is also 28 = 1+2+4+7+14 and the number of proper divisors of 28 is 5, then 28-5 = 23.

CROSSREFS

Cf. A000396, A001065, A032741, A133033, A152770.

Sequence in context: A133338 A116986 A171777 * A134050 A101191 A127900

Adjacent sequences:  A154893 A154894 A154895 * A154897 A154898 A154899

KEYWORD

nonn

AUTHOR

Omar E. Pol (info(AT)polprimos.com), Jan 25 2009

EXTENSIONS

More terms from Max Alekseyev (maxale(AT)gmail.com), Dec 12 2011

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Last modified February 14 11:36 EST 2012. Contains 205623 sequences.