login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A102789 Integer part of n#/((p-11)# 11#), where p=preceding prime to n. 0
0, 0, 0, 0, 0, 6, 7, 19, 41, 5, 8, 14, 20, 28, 1327, 46, 1, 82, 104, 125, 150, 177, 207, 252, 3, 4, 436, 46741, 52523, 58764, 0, 7, 986, 1079, 8, 9, 1529, 11, 1850, 2038, 13, 2426, 14, 15, 3143, 625601, 0, 0, 21, 5018, 1169257, 5520, 5809, 26, 27, 29, 30, 8299, 8741 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,6

COMMENTS

0# = 1# = 2 by convention.

LINKS

Table of n, a(n) for n=2..60.

FORMULA

n# = product of primes <= n. 0#=1#=2. n#/((p-r)# r#) is analogous to the number of combinations of n things taken r at a time: C(n, r) = n!/((n-r)! r!) where factorial ! is replaced by primorial # and n is replaced with the preceding prime to n.

PROG

(PARI) c(n, r) = { local(p); forprime(p=2, n, print1(floor(primorial(p)/primorial(p-r)/primorial(r)+.0)", ") ) } primorial(n) = \ The product of primes <= n using the pari primelimit. { local(p1, x); if(n==0||n==1, return(2)); p1=1; forprime(x=2, n, p1*=x); return(p1) }

CROSSREFS

Sequence in context: A028324 A074342 A329072 * A297556 A286969 A285913

Adjacent sequences:  A102786 A102787 A102788 * A102790 A102791 A102792

KEYWORD

easy,nonn

AUTHOR

Cino Hilliard, Feb 25 2005

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 8 08:06 EDT 2020. Contains 335514 sequences. (Running on oeis4.)