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 A345189 #10 May 21 2022 08:28:57 %S A345189 1,1,6,41,330,2882,26604,255313,2521986,25473638,261898548,2731724778, %T A345189 28836047844,307477681188,3306988334808,35833139582529, %U A345189 390803960909106,4286644113507902,47258491871201508,523372307883323566,5819831138546794860,64954314678710555612,727371707764232349672 %N A345189 Number of rows with the value "false" in the Kleene truth tables of all bracketed formulae with n distinct propositions p1, ..., pn connected by the binary connective of implication. %H A345189 G. C. Greubel, <a href="/A345189/b345189.txt">Table of n, a(n) for n = 1..925</a> %H A345189 Volkan Yildiz, <a href="https://arxiv.org/abs/2106.04728">Notes on algebraic structure of truth tables of bracketed formulae connected by implications</a>, arXiv:2106.04728 [math.CO], 2021. %F A345189 G.f.: (-2-sqrt(1-12*x)+sqrt(5+24*x+4*sqrt(1-12*x)))/6. %F A345189 a(n) = 2*A005159(n-1) - A345190(n). - _G. C. Greubel_, May 20 2022 %t A345189 CoefficientList[Series[(-2 -Sqrt[1-12*x] +Sqrt[5 +24*x +4*Sqrt[1-12*x]])/6, {x, 0, 40}], x]//Rest (* _G. C. Greubel_, May 20 2022 *) %o A345189 (PARI) my(x='x+O('x^30)); Vec((-2-sqrt(1-12*x)+sqrt(5+24*x+4*sqrt(1-12*x)))/6) %o A345189 (SageMath) %o A345189 def A345189_list(prec): %o A345189 P.<x> = PowerSeriesRing(ZZ, prec) %o A345189 return P( (-2-sqrt(1-12*x)+sqrt(5+24*x+4*sqrt(1-12*x)))/6 ).list() %o A345189 a=A345189_list(40); a[1:] # _G. C. Greubel_, May 20 2022 %Y A345189 Cf. A005159 (unknown rows, shifted), A025226 (all rows), A345190 (true rows). %K A345189 nonn %O A345189 1,3 %A A345189 _Michel Marcus_, Jun 10 2021