A160257 a(n) = b(n+2)*b(n+1)/b(n), where b() = A160256().

6, 6, 8, 12, 12, 18, 32, 27, 16, 5, 25, 15, 6, 108, 20, 64, 25, 21, 14, 240, 21, 270, 28, 320, 35, 375, 42, 432, 49, 110, 22, 1680, 33, 1890, 44, 2240, 55, 2625, 66, 3024, 77, 3430, 88, 3840, 99, 4725, 11, 567, 55, 168, 110, 126, 1320, 378, 2640, 1134, 3520, 1701

Offset

1,1

Comments

By definition, each term of this sequence is a positive integer.

Links

Alois P. Heinz, Table of n, a(n) for n = 1..10000

Maple

bb:= proc(n) option remember; false end: b:= proc(n) option remember; local k, m; if n<3 then bb(n):= true; n else m:= denom(b(n-1) /b(n-2)); for k from m by m while bb(k) do od; bb(k):= true; k fi end: a:= n-> b(n+2) *b(n+1) /b(n): seq(a(n), n=1..100); # Alois P. Heinz, May 18 2009

Mathematica

bb[_] = False;
b[n_] := b[n] = Module[{k, m}, If[n<3, bb[n] = True; n, m = Denominator[ b[n-1]/b[n-2]]; For[k = m, bb[k], k += m]; bb[k] = True; k]];
a[n_] := b[n+2] b[n+1]/b[n];
Array[a, 100] (* Jean-François Alcover, Nov 12 2020, after Alois P. Heinz *)

Crossrefs

Cf. A075076, A160256.

Sequence in context: A195707 A175217 A000509 * A315830 A183042 A351516

Adjacent sequences: A160254 A160255 A160256 * A160258 A160259 A160260

Keyword

nonn,look

Author

Leroy Quet, May 06 2009

Extensions

More terms from Alois P. Heinz, May 18 2009

Status

approved