A191836 The slowest growing sequence that satisfies: a(1) = 1, a(n) is a multiple of n and a(n-1), and a(n) > a(n-1).

1, 2, 6, 12, 60, 120, 840, 1680, 5040, 10080, 110880, 221760, 2882880, 5765760, 11531520, 23063040, 392071680, 784143360, 14898723840, 29797447680, 59594895360, 119189790720, 2741365186560, 5482730373120, 27413651865600, 54827303731200, 164481911193600, 328963822387200

Offset: 1

Author

José María Grau Ribas, Jun 17 2011

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A072486.

Programs

Mathematica

a[1]=1; a[n_]:=a[n]=If[LCM[n,a[n-1]]==a[n-1],2 *a[n-1],LCM[n,a[n-1]]]

Formula

a(n) = A072486(n) for n < 15.

a(1) = 1; for n > 1, a(n) = a(n-1) * (if n is a prime power p^k then p else 2). - Franklin T. Adams-Watters, Jan 13 2012

Extensions

a(26)-a(28) from Amiram Eldar, Jun 28 2024