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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 (list; graph; refs; listen; history; text; internal format)
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).

LINKS

Table of n, a(n) for n=1..10.

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

Cf. A087315, A076265, A076265.

Sequence in context: A079264 A006939 A152686 * A158261 A215956 A251182

Adjacent sequences:  A131687 A131688 A131689 * A131691 A131692 A131693

KEYWORD

nonn

AUTHOR

Darse Billings, Sep 14 2007

STATUS

approved

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Last modified June 29 18:25 EDT 2022. Contains 354913 sequences. (Running on oeis4.)