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 A074587 #14 Mar 31 2012 20:55:21 %S A074587 1,3,7,18,37,85,171,364,736,1513,3027,6168,12337,24849,49743,99872, %T A074587 199745,400322,800645,1602862,3205903,6414837,12829675,25665996, %U A074587 51332030,102676401,205353546,410732134,821464269,1642979927,3285959855 %N A074587 Sum of the coefficients of the n-th Moebius polynomial, M(n,x), where M(n,-1) = mu(n), the Moebius function of n. %C A074587 It seems that a(n+1)>2*a(n). - _Benoit Cloitre_, Aug 26 2002 %C A074587 a(n+1)=2*a(n)+1 if and only if n+1 is prime. - _Benoit Cloitre_, Dec 04 2002 %H A074587 T. D. Noe, <a href="/A074587/b074587.txt">Table of n, a(n) for n=1..300</a> %F A074587 a(n) = M(n, 1) (see A074586 for definition of M(n, x)). a(n) mod 2 = A008966(n). a(n) is asymptotic to c*2^n with c=1.530191414016549187154362361492633020259512374111... _Benoit Cloitre_, Dec 04 2002 %F A074587 a(1)=1 a(n)=1+sum(i=1, n-1, floor(n/i)*a(i)). - _Benoit Cloitre_, Dec 04 2002 %e A074587 a(5) = M(5,1) = 1+9+15+10+2 = 37, since M(5,x) = 1 + 9x +15x^2 +10x^3 + 2x^4. %t A074587 m[n_, x_] := m[n, x]=1+x*Sum[m[i, x]Floor[n/i], {i, 1, n-1}]; Table[m[n, 1], {n, 1, 40}] %Y A074587 Cf. A074586. %Y A074587 First column of A169659. [From Mats Granvik, _Paul D. Hanna_, Apr 05 2010] %K A074587 easy,nice,nonn %O A074587 1,2 %A A074587 _Paul D. Hanna_, Aug 25 2002 %E A074587 Cross reference corrected by _Mats Granvik_, Apr 23 2010