OFFSET
0,2
COMMENTS
Original name: Sorting numbers (see Motzkin article for details).
For n>0, a(n) is also the maximum term in row n of the triangle in A227450. - Danny Rorabaugh, Oct 24 2015
REFERENCES
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
Alois P. Heinz, Table of n, a(n) for n = 0..250
Victor Meally, Comparison of several sequences given in Motzkin's paper "Sorting numbers for cylinders...", letter to N. J. A. Sloane, N. D.
T. S. Motzkin, Sorting numbers for cylinders and other classification numbers, in Combinatorics, Proc. Symp. Pure Math. 19, AMS, 1971, pp. 167-176. [Annotated, scanned copy]
OEIS Wiki, Sorting numbers
FORMULA
a(n) = max{2^k*stirling2(n,k), k=0..n}. - Sean A. Irvine, Mar 26 2013
MAPLE
a:= n-> max(seq(2^k*Stirling2(n, k), k=0..n)):
seq(a(n), n=0..30); # Alois P. Heinz, Mar 26 2013
MATHEMATICA
a[n_] := Max[Table[2^k*StirlingS2[n, k], {k, 0, n}]]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Feb 25 2015 *)
PROG
(PARI) a(n) = vecmax(vector(n+1, k, 2^(k-1)*stirling(n, k-1, 2))); \\ Michel Marcus, Feb 25 2015
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
EXTENSIONS
More terms from Sean A. Irvine, Mar 26 2013
New name from Danny Rorabaugh, Oct 24 2015
STATUS
approved