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%I #5 Oct 01 2013 17:58:08
%S 15,105,77,143,221,323,437,29,899,37,1517,1763,2021,53,59,3599,67,
%T 4757,5183,79,6557,89,97,9797,10403,11021,11663,12317,127,16637,137,
%U 19043,149,22499,157,163,27221,173,179,32399,191,36863,38021,39203,211,223
%N Integer part of n#/(p-5)#, where p=preceding prime to n.
%C 0# = 1# = 2 by convention.
%F n# = product of primes <= n. 0#=1#=2. n#/(p-r)# is analogous to the number of permutations of n things taken r at a time: P(n, r) = n!/(n-r)! where factorial ! is replaced by primorial # and n is replaced with the preceding prime to n.
%o (PARI) perm(n,r) = { local(p); forprime(p=r,n, print1(floor(primorial(p)/primorial(p-r))",") ) } 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) }
%K easy,nonn
%O 5,1
%A _Cino Hilliard_, Feb 25 2005
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