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 A332863 #24 Apr 14 2022 01:20:57 %S A332863 0,0,4,17,46,116,288,683,1548,3403,7320,15461,32146,65954,133800, %T A332863 268804,535434,1058533,2078732,4057858,7878814,15223495,29285368, %U A332863 56109673,107108104,203766859,386443052,730768044,1378180568,2592664120,4866008208,9112796113 %N A332863 Total binary weight squared of all A005251(n) binary sequences of length n not containing any isolated 1's. %H A332863 G. C. Greubel, <a href="/A332863/b332863.txt">Table of n, a(n) for n = 0..1000</a> %H A332863 Steven Finch, <a href="https://arxiv.org/abs/2003.09458">Cantor-solus and Cantor-multus distributions</a>, arXiv:2003.09458 [math.CO], 2020. %H A332863 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (6,-15,23,-27,24,-16,9,-3,1). %F A332863 G.f.: x^2*(4-7*x+4*x^2+3*x^3-x^4)/(1-2*x+x^2-x^3)^3. %F A332863 a(n) = Sum_{k=1..n} k^2 * A097230(n,k). - _Alois P. Heinz_, Mar 03 2020 %e A332863 The only two 2-bitstrings without isolated 1's are 00 and 11. The bitsums squared of these are 0 and 4. Adding these give a(2)=4. %e A332863 The only four 3-bitstrings without isolated 1's are 000, 011, 110 and 111. The bitsums squared of these are 0, 4, 4 and 9. Adding these give a(3)=17. %t A332863 LinearRecurrence[{6,-15,23,-27,24,-16,9,-3,1}, {0,0,4,17,46,116,288,683,1548}, 40] (* _G. C. Greubel_, Apr 13 2022 *) %o A332863 (Magma) R<x>:=PowerSeriesRing(Integers(), 40); [0,0] cat Coefficients(R!( x^2*(4-7*x+4*x^2+3*x^3-x^4)/(1-2*x+x^2-x^3)^3 )); // _G. C. Greubel_, Apr 13 2022 %o A332863 (SageMath) %o A332863 def A332863_list(prec): %o A332863 P.<x> = PowerSeriesRing(ZZ, prec) %o A332863 return P( x^2*(4-7*x+4*x^2+3*x^3-x^4)/(1-2*x+x^2-x^3)^3 ).list() %o A332863 A332863_list(40) # _G. C. Greubel_, Apr 13 2022 %Y A332863 Cf. A005251, A097230, A259966. %K A332863 nonn,easy %O A332863 0,3 %A A332863 _Steven Finch_, Feb 27 2020