OFFSET
1,3
COMMENTS
Consider the harmonic progression 1, 1/2, 1/3, 1/4, 1/5, ...; then a(n) = floor(reciprocal of the sum of next n terms of this harmonic progression).
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..225
EXAMPLE
a(4) = floor(7*8*9*10/(7+8+9+10)) = floor(5040/34) = 148.
MAPLE
a:=n->floor((n*(n+1)/2)!/(n*(n-1)/2)!/(n*(n^2+1)/2)): seq(a(n), n=1..16); # Emeric Deutsch, Aug 04 2005
MATHEMATICA
Table[Floor[2*Binomial[n+1, 2]!/(Binomial[n, 2]!*n*(n^2+1))], {n, 1, 25}] (* G. C. Greubel, Mar 07 2019 *)
PROG
(PARI) k=1; for(n=0, 20, p=1; s=0; for(i=k, k+n, s=s+i; p=p*i); k=k+n+1; print1(floor(p/s)", "))
(Magma) [Floor(2*Gamma((n^2+n+2)/2)/(Gamma((n^2-n+2)/2)*n*(n^2+1))): n in [1..25]]; // G. C. Greubel, Mar 07 2019
(Sage) [floor(2*factorial((n+1)*n/2)/(factorial(n*(n-1)/2)*n*(n^2+1))) for n in (1..25)] # G. C. Greubel, Mar 07 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Sep 19 2002
EXTENSIONS
More terms from Ralf Stephan, Mar 31 2003
Name edited by Jon E. Schoenfield, Mar 07 2019
STATUS
approved