A221132 a(n) = lcm(a(n-1), n^2 + n + 1) for n > 1 with a(1) = 1.

1, 7, 91, 273, 8463, 363909, 6914271, 504741783, 504741783, 18675445971, 18675445971, 2932045017447, 178854746064267, 37738351419560337, 9094942692114041217, 9094942692114041217, 2792147406479010653619, 136815222917471522027331

Offset

1,2

Comments

Not the same as if a(n) = lcm(f(1),f(2),...,f(n))/3 with f(x)=x^2+x+1 and a(1)=f(1).

Links

Table of n, a(n) for n=1..18.

Mathematica

f[x_] := x^2 + x + 1; a[1] = 1; a[n_] := LCM[f[n], a[n - 1]]; Array[a, 18]

Crossrefs

Cf. A193181.

Sequence in context: A123694 A319978 A085026 * A181475 A374094 A249640

Adjacent sequences: A221129 A221130 A221131 * A221133 A221134 A221135

Keyword

nonn

Author

Robert G. Wilson v, Jan 02 2013

Status

approved