This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A000654 M2173 N0868 #45 Jun 11 2025 17:51:46 %S A000654 1,2,52,142090700,17844701940501123640681816160, %T A000654 59757436204078657410908164193971330396709572693816353610758085074676243846093824 %N A000654 Invertible Boolean functions of n variables. %C A000654 Equivalence classes of invertible maps from {0,1}^n to {0,1}^n, under action of permutation and complementation of variables on domain and range. - _Sean A. Irvine_, Mar 16 2011 %D A000654 M. A. Harrison, The number of classes of invertible Boolean functions, J. ACM 10 (1963), 25-28. %D A000654 C. S. Lorens, Invertible Boolean functions, IEEE Trans. Electron. Computers, EC-13 (1964), 529-541. %D A000654 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %D A000654 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A000654 Adam P. Goucher, <a href="/A000654/b000654.txt">Table of n, a(n) for n = 1..7</a> %H A000654 M. A. Harrison, <a href="/A000653/a000653.pdf">The number of classes of invertible Boolean functions</a>, J. ACM 10 (1963), 25-28. [Annotated scan of page 27 only] %H A000654 M. A. Harrison, <a href="/A000370/a000370.pdf">The number of equivalence classes of Boolean functions under groups containing negation</a>, IEEE Trans. Electron. Comput. 12 (1963), 559-561. [Annotated scanned copy] %H A000654 C. S. Lorens, <a href="http://dx.doi.org/10.1109/PGEC.1964.263724">Invertible Boolean functions</a>, IEEE Trans. Electron. Computers, EC-13 (1964), 529-541. %H A000654 C. S. Lorens, <a href="/A000722/a000722.pdf">Invertible Boolean functions</a>, IEEE Trans. Electron. Computers, EC-13 (1964), 529-541. [Annotated scan of page 530 only] %H A000654 Qing-bin Luo, Jin-zhao Wu, and Chen Lin, <a href="https://doi.org/10.1007/s10773-020-04508-y">Computing the Number of the Equivalence Classes for Reversible Logic Functions</a>, Int'l J. of Theor. Phys. (2020) Vol. 59, 2384-2396. %H A000654 Ludovic Schwob, <a href="https://arxiv.org/abs/2506.04007">On the enumeration of double cosets and self-inverse double cosets</a>, arXiv:2506.04007 [math.CO], 2025. See p. 10. %H A000654 <a href="/index/Bo#Boolean">Index entries for sequences related to Boolean functions</a> %t A000654 cyclify = %t A000654 Function[{x}, %t A000654 Sort@Tally[Length /@ PermutationCycles[x + 1, Identity]]]; %t A000654 totalweight = %t A000654 Function[{c}, Product[(x[[1]]^x[[2]]) ( x[[2]]!), {x, c}]]; %t A000654 perms = Function[{n}, %t A000654 Flatten[Table[ %t A000654 FromDigits[Permute[IntegerDigits[BitXor[x, a], 2, n], sigma], %t A000654 2], {sigma, Permutations[Range[n]]}, {a, 0, 2^n - 1}, {x, 0, %t A000654 2^n - 1}], 1]]; %t A000654 countit = %t A000654 Function[{n}, %t A000654 Sum[totalweight[x[[1]]] (x[[2]]^2), {x, %t A000654 Tally[cyclify /@ perms[n]]}]/((2^n) (n!))^2]; %t A000654 Table[countit[n], {n, 1, 5}] (* _Adam P. Goucher_, Feb 12 2021 *) %K A000654 nonn %O A000654 1,2 %A A000654 _N. J. A. Sloane_ %E A000654 More terms from _Sean A. Irvine_, Mar 15 2011