A007157 - OEIS

%I M3695 #13 Nov 07 2017 18:23:24

%S 0,4,74,43682,160297810086

%N Essentially n-ary operations in Kleene free algebra.

%D J. Berman, ``Free spectra of 3-element algebras,'' in R. S. Freese and O. C. Garcia, editors, Universal Algebra and Lattice Theory (Puebla, 1982), Lect. Notes Math. Vol. 1004, 1983.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H J. Berman, <a href="/A007153/a007153.pdf">Free spectra of 3-element algebras</a>, R. S. Freese and O. C. Garcia, editors, Universal Algebra and Lattice Theory (Puebla, 1982), Lect. Notes Math. Vol. 1004, 1983. (Annotated scanned copy)

%F a(n) = Sum_{i=0..n} (-1)^(n-i) * binomial(n, i) * A007154(i). - _Sean A. Irvine_, Nov 05 2017

%Y Cf. A007154.

%K nonn

%O 0,2

%A _N. J. A. Sloane_.

%E Title improved by _Sean A. Irvine_, Nov 05 2017