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A054641
GCD of divisor-sum of primorials and primorials itself: a(n) = gcd(A002110(n), A000203(A002110(n))).
2
1, 6, 6, 6, 6, 42, 42, 210, 210, 210, 210, 3990, 3990, 43890, 43890, 43890, 43890, 1360590, 23130030, 23130030, 855811110, 855811110, 855811110, 855811110, 855811110, 855811110, 11125544430, 11125544430, 11125544430, 11125544430
OFFSET
1,2
COMMENTS
Values are repeated for several arguments: observed from 1 to 8 times below n=100. Sites of jump seems not so regular.
From a sufficiently high value of n, A002110(n) divides the terms. E.g., from n=27, A002110(8) divides the values of this sequences.
PROG
(PARI) a(n)=gcd(prod(i=1, n, prime(i)), prod(i=1, n, prime(i)+1)) \\ Charles R Greathouse IV, Feb 19 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, May 15 2000
STATUS
approved