A074094 a(1) = 1; for n > 1, a(n) = LCM of next n composite numbers.

1, 12, 360, 1680, 27720, 1965600, 116396280, 758696400, 18465927480, 3962129371200, 5637782470320, 546077803471200, 592841333318073840, 717574218173821008000, 66020319718147594800, 111304867624125438463200

Offset

1,2

Comments

I.e., "next n composite numbers" following those that were used in computing a(n-1); see Example section. - Jon E. Schoenfield, Mar 18 2018

Links

Robert Israel, Table of n, a(n) for n = 1..356

Formula

for n >= 2, a(n) = lcm(A002808(A000217(n-1)...A000217(n)-1)). - Robert Israel, Jan 13 2016

Example

a(2) = lcm(4,6) = 12;
a(3) = lcm(8,9,10) = 360;
a(4) = lcm(12,14,15,16) = 1680.

Maple

comps:= remove(isprime, [$2..10^4]):
N:= floor((sqrt(9+8*nops(comps))-1)/2):
1, seq(ilcm(op(comps[(n-1)*n/2 .. n*(n+1)/2-1])), n=2..N); # Robert Israel, Jan 13 2016

Mathematica

Join[{1}, i = 3; Table[t = {}; c = 0; While[c != n, If[! PrimeQ[i], AppendTo[t, i]; c++]; i++]; LCM @@ t, {n, 2, 16}]] (* Jayanta Basu, Jul 30 2013 *)

Crossrefs

Cf. A000217, A002808.

Sequence in context: A134800 A053068 A046969 * A012553 A128043 A012431

Adjacent sequences: A074091 A074092 A074093 * A074095 A074096 A074097

Keyword

nonn

Author

Amarnath Murthy, Aug 20 2002

Extensions

More terms from Sascha Kurz, Jan 14 2003

Offset corrected by Robert Israel, Jan 13 2016

Status

approved