OFFSET
0,3
REFERENCES
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 429.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
MAPLE
Digits := 60: A000155 := proc(n) round( evalf ( BesselK( n, 1) )); end;
a := proc(n) options remember; if n<3 then n elif n=3 then 7 else a(n-4)+2*(n-3)*a(n-3)+2*(n-1)*a(n-1) fi end: # Mark van Hoeij, Nov 21 2011
series(hypergeom([1, 1], [], 2*x/(1+x^2))*x/(1+x^2), x=0, 20); # Mark van Hoeij, Nov 21 2011
MATHEMATICA
Table[Round[BesselK[n, 1]], {n, 0, 18}] (* Ray Chandler, Nov 28 2006 *)
PROG
(PARI) a(n)=round(besselk(n, 1)) \\ Charles R Greathouse IV, May 11 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Extended by Ray Chandler, Nov 28 2006
More accurate definition by Sean A. Irvine, Mar 28 2010
STATUS
approved