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A366809
The sum of the divisors of prime(n)#-1 where p# is the product of all the primes from 2 to p inclusive.
3
1, 6, 30, 240, 2310, 30030, 518940, 9943560, 230876448, 6551588160, 200561595684, 7471933410000, 304250263527210, 13082853940673340, 618109122639794688, 32589631537463089128, 1922760350251477679196, 117386696543681561301312, 7906535060701218163040640
OFFSET
1,2
FORMULA
a(n) = sigma(prime(n)#-1) = A000230(A057588(n)).
EXAMPLE
a(4)=240 because the divisors of 7#-1 = 209 are {1, 11, 19, 209}.
MAPLE
seq(numtheory[sigma](mul(ithprime(k), k=1..n)-1), n=1..30);
CROSSREFS
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 23 2023
STATUS
approved