A025552 LCM of {C(0,0), C(1,0), ..., C(n, floor(n/2))}.

1, 1, 2, 6, 6, 30, 60, 420, 420, 1260, 1260, 13860, 13860, 180180, 360360, 360360, 360360, 6126120, 6126120, 116396280, 116396280, 116396280, 116396280, 2677114440, 2677114440, 13385572200, 13385572200, 40156716600, 40156716600, 1164544781400

Offset

0,3

Links

Robert P. P. McKone, Table of n, a(n) for n = 0..199

Formula

Let b(n) = 2 if n = 2^m or n = 2^m + 1 for some m, otherwise 1; then a(n) = lcm({1,2,...,n}) / b(n). - Peter Luschny, Jun 26 2009

Maple

LCM := proc(n) option remember; if n < 2 then 1 else ilcm(n, LCM(n-1)) fi end;
a := proc(n) local i; add(i, i=convert(2*iquo(n+2, 2), base, 2)); `if`(%=1, LCM(n), LCM(n)/2) end: # Peter Luschny, Jun 26 2009

Mathematica

l[1] = 1; l[n_Integer?NonNegative] := l[n] = LCM[n, l[n - 1]];
a[0] = 1; a[n_Integer?NonNegative] := a[n] = Module[{s}, s = Total[IntegerDigits[2*Quotient[n + 2, 2], 2]]; If[s == 1, l[n], l[n]/2]];
Table[a[n], {n, 0, 29}] (* Robert P. P. McKone, Oct 31 2023 *)

Crossrefs

Cf. A003418. - Peter Luschny, Jun 26 2009

Sequence in context: A034386 A083907 A084343 * A284008 A284576 A060114

Adjacent sequences: A025549 A025550 A025551 * A025553 A025554 A025555

Keyword

nonn

Author

Clark Kimberling

Extensions

Offset corrected by Peter Luschny, Jun 26 2009

Status

approved