%I A002671 M5174 N2246
%S A002671 1,24,1920,322560,92897280,40874803200,25505877196800,
%T A002671 21424936845312000,23310331287699456000,31888533201572855808000,
%U A002671 53572735778642397757440000,108431217215972213061058560000
%N A002671 4^n*(2*n+1)!.
%D A002671 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A002671 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A002671 H. E. Salzer, Tables of coefficients for obtaining central differences 
               from their derivatives, Journal of Mathematics and Physics, 42 (1963), 
               162-165. Note that there is a mistake in the definition of this sequence 
               on line 2 of page 164.
%o A002671 (PARI) a(n)=4^n*(2*n+1)!
%Y A002671 A002671(n) = A002866(2n+1).
%Y A002671 Sequence in context: A166788 A123794 A006685 this_sequence A003738 A001501 
               A054005
%Y A002671 Adjacent sequences: A002668 A002669 A002670 this_sequence A002672 A002673 
               A002674
%K A002671 nonn,easy
%O A002671 0,2
%A A002671 N. J. A. Sloane (njas(AT)research.att.com), Simon Plouffe (simon.plouffe(AT)gmail.com)
%E A002671 More terms from Michael Somos