A060779 a(n) = lcm(tau(n+1), tau(n)), where tau = A000005.

2, 2, 6, 6, 4, 4, 4, 12, 12, 4, 6, 6, 4, 4, 20, 10, 6, 6, 6, 12, 4, 4, 8, 24, 12, 4, 12, 6, 8, 8, 6, 12, 4, 4, 36, 18, 4, 4, 8, 8, 8, 8, 6, 6, 12, 4, 10, 30, 6, 12, 12, 6, 8, 8, 8, 8, 4, 4, 12, 12, 4, 12, 42, 28, 8, 8, 6, 12, 8, 8, 12, 12, 4, 12, 6, 12, 8, 8, 10, 10, 20, 4, 12, 12, 4, 4, 8, 8, 12

Offset: 1

Author

Labos Elemer, Apr 26 2001

Keywords

• nonn

Links

• Harry J. Smith, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A057921, A000005.

Programs

Mathematica

LCM@@#&/@Partition[DivisorSigma[0,Range[90]],2,1] (* Harvey P. Dale, Jan 27 2025 *)

PARI

a(n) = { lcm(numdiv(n), numdiv(n+1)) } \\ Harry J. Smith, Jul 11 2009

Formula

a(n) = lcm(A000005(n+1), A000005(n)).