login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A131690 a(n) = Product prime1(k)^prime1(n-k+1), k = 1 to n. 0

%I #3 Mar 31 2012 10:25:49

%S 1,2,12,360,151200,2095632000,7551819475200000,

%T 7286477990937425280000000,16326289449604557795871699200000000000,

%U 48235535472088469901966394717904245153920000000000000

%N a(n) = Product prime1(k)^prime1(n-k+1), k = 1 to n.

%C 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).

%F a(n) = Product prime1(k)^prime1(n-k+1), k = 1 to n, where prime1 is the sequence of primes prepended with 1.

%e a(5) = 1^7 * 2^5 * 3^3 * 5^2 * 7^1 = 151200

%Y Cf. A087315, A076265, A076265.

%K nonn

%O 1,2

%A _Darse Billings_, Sep 14 2007

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 24 02:46 EDT 2024. Contains 371917 sequences. (Running on oeis4.)