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 A291286 a(0)=1, a(1)=2, thereafter a(n) = n*a(n-1)+(n-1)*(n-2)*a(n-2). 1
 1, 2, 4, 16, 88, 632, 5552, 57824, 695776, 9500128, 145097152, 2451080192, 45373649024, 913400022656, 19865889564928, 464227147597312, 11599471170191872, 308605525316616704, 8709955613991289856, 259922447412719218688, 8177253768239405504512 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Table of n, a(n) for n=0..20. MAPLE f:=proc(n) option remember; if n <= 1 then n+1 else n*f(n-1)+(n-1)*(n-2)*f(n-2); fi; end; [seq(f(n), n=0..40)]; CROSSREFS A244430 and A291287 have the same recurrence. Sequence in context: A212432 A351287 A013115 * A007171 A058136 A156335 Adjacent sequences: A291283 A291284 A291285 * A291287 A291288 A291289 KEYWORD nonn AUTHOR N. J. A. Sloane, Aug 27 2017 STATUS approved

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Last modified August 8 06:29 EDT 2024. Contains 375020 sequences. (Running on oeis4.)