A203811 Denominators of s(i) = s(i-1) - (1/i)*sign(s(i-1)) with s(1) = 1.

1, 2, 6, 12, 60, 20, 140, 280, 2520, 2520, 27720, 27720, 360360, 360360, 72072, 144144, 2450448, 2450448, 46558512, 232792560, 232792560, 232792560, 5354228880, 5354228880, 26771144400, 26771144400, 80313433200, 80313433200, 2329089562800, 2329089562800

Offset

1,2

Comments

Numerators are given in A203810. The first 14 terms coincide with those of A002805.

Links

Hugo Pfoertner, Table of n, a(n) for n = 1..200

Example

See A203810.

Mathematica

nxt[{n_, a_}]:={n+1, a-1/(n+1) Sign[a]}; NestList[nxt, {1, 1}, 30][[All, 2]]//Denominator (* Harvey P. Dale, Jun 06 2021 *)

Crossrefs

Cf. A002805, A203810 (numerators), A203812.

Sequence in context: A119862 A111936 A232090 * A002805 A231693 A375524

Adjacent sequences: A203808 A203809 A203810 * A203812 A203813 A203814

Keyword

nonn,frac

Author

Hugo Pfoertner and Rainer Rosenthal, Jan 06 2012

Status

approved