A192676 Floor-Sqrt transform of derangement numbers (A000166).

1, 0, 1, 1, 3, 6, 16, 43, 121, 365, 1155, 3832, 13274, 47862, 179084, 693589, 2774358, 11438972, 48531450, 211543687, 946052129, 4335355493, 20334619731, 97521410321, 477755388567, 2388776942837, 12180420245150, 63291320166423, 334906186618646, 1803525009870353

Offset

0,5

Links

Table of n, a(n) for n=0..29.

Formula

a(n) = floor(sqrt(derangements(n))).

Mathematica

FSFromExpSeries[f_, x_, n_] := Map[Floor[Sqrt[#]]&, CoefficientList[Series[f, {x, 0, n}], x]Table[k!, {k, 0, n}]]
FSFromExpSeries[Exp[-x]/(1-x), x, 100]

Crossrefs

Cf. A000166.

Sequence in context: A371705 A007561 A274295 * A202846 A107269 A333026

Adjacent sequences: A192673 A192674 A192675 * A192677 A192678 A192679

Keyword

nonn

Author

Emanuele Munarini, Jul 07 2011

Status

approved