A109850 -id:A109850 - cp's OEIS frontend

A109849 a(1) = 1, a(2) = 2; a(n) = lcm(n, a(n-2)), a(n+1) = lcm((n+1), a(n-3)) and so on until a(2n-1) = lcm(2n-1, a(1)). Then a(2n) = lcm(2n, a(2n-2)) and so on.

1, 2, 3, 4, 5, 12, 21, 8, 9, 40, 231, 12, 65, 28, 15, 16, 17, 144, 285, 140, 1365, 132, 5313, 120, 225, 104, 189, 84, 145, 60, 93, 32, 33, 544, 3255, 180, 5365, 1596, 2457, 520, 9225, 840, 228459, 132, 4095, 3220, 13395, 144, 833, 400, 255, 364, 3445, 108, 1155

Offset: 1

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Amarnath Murthy, Jul 06 2005

nonn

Another bootstrap sequence. 12 appears twice.

12 60 65 104 120 132 144 252 255 400 912 1008 1020 1980 2112 2457 4092 4095 ... are the smallest numbers that appear twice, with 4095 being the smallest number that appears three times. - Joshua Zucker, May 04 2006

Ivan Neretin, Table of n, a(n) for n = 1..8193

Cf. A109850.

For n > 2, a(n) = lcm(n, a(A080079(n-2))). - Ivan Neretin, Apr 30 2016

More terms from Joshua Zucker, May 04 2006

cp's OEIS Frontend

A109849 a(1) = 1, a(2) = 2; a(n) = lcm(n, a(n-2)), a(n+1) = lcm((n+1), a(n-3)) and so on until a(2n-1) = lcm(2n-1, a(1)). Then a(2n) = lcm(2n, a(2n-2)) and so on.

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