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 A006041 a(n+1) = (n^2 - 1)*a(n) + n + 1. (Formerly M1949) 1
 0, 2, 9, 76, 1145, 27486, 962017, 46176824, 2909139921, 232731193690, 23040388175321, 2764846581038532, 395373061088510089, 66422674262869694966, 12952421481259590518385, 2901342411802148276118256, 739842315009547810410155297, 213074586722749769398124725554, 68823091511448175515594286353961 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 REFERENCES R. K. Guy, personal communication. N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS G. C. Greubel, Table of n, a(n) for n = 1..250 R. K. Guy, Letter to N. J. A. Sloane with attachment, Jun. 1991 Index entries for sequences related to Bessel functions or polynomials FORMULA Nearest integer to BesselI(1, 2)*(n-1)!*(n-1)!*n/(n-1), n>2. MATHEMATICA Join[{0, 2}, Table[Floor[BesselI[1, 2]*(n - 1)!*(n - 1)!*n/(n - 1)], {n, 3, 50}]] (* G. C. Greubel, Aug 16 2017 *) RecurrenceTable[{a[1]==0, a[n+1]==(n^2-1)a[n]+n+1}, a, {n, 20}] (* Harvey P. Dale, May 16 2020 *) PROG (PARI) a(n) = if (n==1, 0, (n^2-2*n)*a(n-1) + n); \\ Michel Marcus, Aug 16 2017 CROSSREFS Sequence in context: A006059 A277406 A182947 * A192551 A121131 A166891 Adjacent sequences: A006038 A006039 A006040 * A006042 A006043 A006044 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Simon Plouffe EXTENSIONS More terms from James A. Sellers, May 01 2000 STATUS approved

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Last modified February 21 22:50 EST 2024. Contains 370239 sequences. (Running on oeis4.)