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 A090091 #41 Aug 17 2025 17:42:03 %S A090091 1,1,2,5,15,67,504,9310,1396077,5937876645 %N A090091 Number of groups of order 3^n. %D A090091 G. Bagnera, La composizione dei Gruppi finiti il cui grado e la quinta potenza di un numero primo, Ann. Mat. Pura Appl. (3), 1 (1898), 137-228. %D A090091 Hans Ulrich Besche, Bettina Eick and E. A. O'Brien, A Millennium Project: Constructing Small Groups, International Journal of Algebra and Computation, Vol. 12, No 5 (2002), 623-644. %D A090091 W. Burnside, Theory of Groups of Finite Order, Dover, NY, 1955. %D A090091 Marcus du Sautoy, Symmetry: A Journey into the Patterns of Nature, HarperCollins, 2008, p. 96. %H A090091 David Burrell, <a href="https://doi.org/10.1080/00927872.2023.2169706">The number of p-groups of order 19,683 and new lists of p-groups</a>, Communications in Algebra, Vol. 51 - Issue 6 (2023), 2673-2679. %H A090091 Heiko Dietrich, <a href="http://users.monash.edu/~heikod/icts2016/CPGmain.pdf">Computational aspects of finite p-groups</a>, 2016. %H A090091 Rodney James and John Cannon, <a href="http://dx.doi.org/10.1090/S0025-5718-1969-0238953-8">Computation of isomorphism classes of p-groups</a>, Mathematics of Computation 23.105 (1969): 135-140. %H A090091 M. F. Newman, E. A. O'Brien and M. R. Vaughan-Lee, <a href="http://dx.doi.org/10.1016/j.jalgebra.2003.11.012">Groups and nilpotent Lie rings whose order is the sixth power of a prime</a>, J. Algebra, 278 (2004), 383-401. %H A090091 E. A. O'Brien and M. R. Vaughan-Lee, <a href="http://dx.doi.org/10.1016/j.jalgebra.2005.01.019">The groups of order p^7 for odd prime p</a>, J. Algebra 292, 243-258, 2005. [_David Radcliffe_, Feb 24 2010] %H A090091 Michael Vaughan-Lee, <a href="https://dx.doi.org/10.1365/s13291-012-0039-x">Graham Higman’s PORC Conjecture</a>, Jahresbericht der Deutschen Mathematiker-Vereinigung Vol. 114 (2012), 89-16. %H A090091 Michael Vaughan-Lee, <a href="http://dx.doi.org/10.22108/ijgt.2015.5758">Groups of order p^8 and exponent p</a>, International Journal of Group Theory Vol. 4 (2015), 25-42. %H A090091 Brett Edward Witty, <a href="https://www.brettwitty.net/pages/phd.html">Enumeration of groups of prime-power order</a>, PhD thesis, 2006. %F A090091 a(n) = A000001(3^n). %e A090091 G.f. = 1 + x + 2*x^2 + 5*x^3 + 15*x^4 + 67*x^5 + 504*x^6 + 9310*x^7 + ... %p A090091 with(GroupTheory): seq(NumGroups(3^n),n=0..8); # _Muniru A Asiru_, Oct 17 2018 %o A090091 (GAP) A090091 := List([0..7],n -> NumberSmallGroups(3^n)); # _Muniru A Asiru_, Oct 15 2017 %Y A090091 Cf. A000001, A000679, A090130, A090140. %K A090091 nonn,hard,more %O A090091 0,3 %A A090091 _Eamonn O'Brien_, Jan 22 2004 %E A090091 a(7) from _David Radcliffe_, Feb 24 2010 %E A090091 a(8) from _Muniru A Asiru_, Oct 17 2018 %E A090091 a(9) from _David Burrell_, Sep 01 2023