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A131690
a(n) = Product prime1(k)^prime1(n-k+1), k = 1 to n.
0
1, 2, 12, 360, 151200, 2095632000, 7551819475200000, 7286477990937425280000000, 16326289449604557795871699200000000000, 48235535472088469901966394717904245153920000000000000
OFFSET
1,2
COMMENTS
Exponents of the prime factorization are the primes in reverse order. Similar to A087315, but where the largest prime factor has an exponent of one instead of two (and 1^n is understood to be the first term).
FORMULA
a(n) = Product prime1(k)^prime1(n-k+1), k = 1 to n, where prime1 is the sequence of primes prepended with 1.
EXAMPLE
a(5) = 1^7 * 2^5 * 3^3 * 5^2 * 7^1 = 151200
CROSSREFS
KEYWORD
nonn
AUTHOR
Darse Billings, Sep 14 2007
STATUS
approved