cp's OEIS Frontend

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.

A117160 Column 1 of triangle A112682; also equals row sums of A112682 (with offset).

Original entry on oeis.org

1, 1, 2, 4, 9, 19, 43, 94, 210, 464, 1035, 2295, 5111, 11352, 25259, 56145, 124888, 277669, 617554, 1373201, 3053883, 6790995, 15102178, 33583784, 74684504, 166082706, 369337117, 821331578, 1826484804, 4061741926, 9032530513
Offset: 1

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Author

Wouter Meeussen and Paul D. Hanna, Feb 28 2006

Keywords

Comments

G.f.: A(x) = g.f. of A117169 (Shift-Moebius[1,1,1,1,...]) divided by the g.f. of A117166 (Shift-Moebius[1,0,0,0,...]) (see A117165 for the Shift-Moebius transform coefficients).
Limit_{n->oo} a(n+1)/a(n) = 2.223805416529545241557...

Crossrefs

Cf. A112682, A117165 (Shift-Moebius), A117169, A117166, A117161.

Programs

  • PARI
    {a(n)=if(n<1,0,SM=prod(i=0,n,matrix(n,n,r,c,if(r>=c, if((r+n-i)%(c+n-i)==0,moebius((r+n-i)/(c+n-i)),0)))); U=SM*vector(n,i,1)~;V=SM*vector(n,i,if(i==1,1,0))~; return(Vec(Ser(U)/Ser(V))[n]))}