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 A000155 Nearest integer to modified Bessel function K_n(1). (Formerly M1810 N0716) 2
 0, 1, 2, 7, 44, 361, 3654, 44207, 622552, 10005041, 180713290, 3624270839, 79914671748, 1921576392793, 50040900884366, 1403066801155039, 42142044935535536, 1349948504738292193, 45940391206037470098 (list; graph; refs; listen; history; text; internal format)
 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 _*) PROG (PARI) a(n)=round(besselk(n, 1)) \\ Charles R Greathouse IV, May 11 2016 CROSSREFS Sequence in context: A158107 A145073 A111561 * A077045 A178012 A194018 Adjacent sequences:  A000152 A000153 A000154 * A000156 A000157 A000158 KEYWORD nonn AUTHOR EXTENSIONS Extended by Ray Chandler, Nov 28 2006 More accurate definition by Sean A. Irvine, Mar 28 2010 STATUS approved

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