OFFSET
1,2
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
EXAMPLE
286 = 2*11*13 is squarefree and 286 = (13*12*11)/(1*2*3) = Binomial(13,3), so 286 is a term.
MAPLE
with(numtheory): A070755:=n->`if`(mobius(n*(n+1)*(n+2)/6)^2=1, n*(n+1)*(n+2)/6, NULL): seq(A070755(n), n=1..100); # Wesley Ivan Hurt, Oct 10 2014
PROG
(PARI) list(lim)=my(v=List(), t); forstep(n=1, sqrtnint(lim\1*6, 3), [2, 2, 4], if(issquarefree(n/gcd(n, 6)) && issquarefree((n+1)/gcd(n+1, 6)) && issquarefree((n+2)/gcd(n+2, 6)) && (t=binomial(n+2, 3))<=lim, listput(v, t))); Vec(v) \\ Charles R Greathouse IV, Feb 22 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, May 14 2002
STATUS
approved