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 A034349 #22 Jul 08 2025 20:16:29 %S A034349 0,0,0,0,0,0,0,1,8,47,277,1775,12616,102445,957357,10174566,119235347, %T A034349 1482297912,18884450721,240477821389,3012879828566,36800049400028, %U A034349 436068618826236,5001537857507095,55482177298724426,595303034603214108,6181562837200509792,62170512250565592346 %N A034349 Number of binary [ n,8 ] codes without 0 columns. %C A034349 To find the g.f., modify the Sage program below (cf. function f). It is very complicated to write it here. - _Petros Hadjicostas_, Oct 07 2019 %H A034349 Discrete algorithms at the University of Bayreuth, <a href="http://www.algorithm.uni-bayreuth.de/en/research/SYMMETRICA/">Symmetrica</a>. %H A034349 Harald Fripertinger, <a href="http://www.mathe2.uni-bayreuth.de/frib/codes/tables.html">Isometry Classes of Codes</a>. %H A034349 Harald Fripertinger, <a href="http://www.mathe2.uni-bayreuth.de/frib/codes/tables_4.html">Snk2: Number of the isometry classes of all binary (n,k)-codes without zero-columns</a>. [See column k=8.] %H A034349 H. Fripertinger and A. Kerber, <a href="https://doi.org/10.1007/3-540-60114-7_15">Isometry classes of indecomposable linear codes</a>. In: G. Cohen, M. Giusti, T. Mora (eds), Applied Algebra, Algebraic Algorithms and Error-Correcting Codes, 11th International Symposium, AAECC 1995, Lect. Notes Comp. Sci. 948 (1995), pp. 194-204. [Here a(n) = S_{n,8,2}.] %H A034349 Petr Lisonek, <a href="https://doi.org/10.1016/j.jcta.2006.06.013">Combinatorial families enumerated by quasi-polynomials</a>, J. Combin. Theory Ser. A 114(4) (2007), 619-630. [See Section 5.] %H A034349 David Slepian, <a href="https://archive.org/details/bstj39-5-1219">Some further theory of group codes</a>, Bell System Tech. J. 39(5) (1960), 1219-1252. %H A034349 David Slepian, <a href="https://doi.org/10.1002/j.1538-7305.1960.tb03958.x">Some further theory of group codes</a>, Bell System Tech. J. 39(5) (1960), 1219-1252. %H A034349 Wikipedia, <a href="https://en.wikipedia.org/wiki/Cycle_index">Cycle index</a>. %H A034349 Wikipedia, <a href="https://en.wikipedia.org/wiki/Projective_linear_group">Projective linear group</a>. %o A034349 (Sage) # Fripertinger's method to find the g.f. of column k >= 2 of A034253 (for small k): %o A034349 def A034253col(k, length): %o A034349 G1 = PSL(k, GF(2)) %o A034349 G2 = PSL(k-1, GF(2)) %o A034349 D1 = G1.cycle_index() %o A034349 D2 = G2.cycle_index() %o A034349 f1 = sum(i[1]*prod(1/(1-x^j) for j in i[0]) for i in D1) %o A034349 f2 = sum(i[1]*prod(1/(1-x^j) for j in i[0]) for i in D2) %o A034349 f = f1 - f2 %o A034349 return f.taylor(x, 0, length).list() %o A034349 # For instance the Taylor expansion for column k = 8 (current sequence) gives %o A034349 print(A034253col(8, 30)) # _Petros Hadjicostas_, Oct 07 2019 %Y A034349 Cf. A034254, A034344, A034345, A034346, A034347, A034348, A253186. %Y A034349 Column k=8 of A034253 and first differences of A034362. %K A034349 nonn %O A034349 1,9 %A A034349 _N. J. A. Sloane_ %E A034349 More terms from _Petros Hadjicostas_, Oct 07 2019