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.

A182669 Floor-sum sequence of r, with r = golden ratio = (1+sqrt(5))/2 and a(1)=1, a(2)=3.

Original entry on oeis.org

1, 3, 6, 11, 14, 19, 22, 24, 27, 32, 35, 37, 40, 43, 45, 48, 53, 56, 58, 61, 64, 66, 69, 71, 74, 77, 79, 82, 87, 90, 92, 95, 98, 100, 103, 105, 108, 111, 113, 116, 119, 121, 124, 126, 129, 132, 134, 137, 139, 142, 145, 147, 150, 153, 155, 158, 160, 163, 166, 168, 171, 173, 174, 176, 179, 181, 184
Offset: 1

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Author

Clark Kimberling, Nov 27 2010

Keywords

Comments

Let S be the set generated by these rules: (1) if m and n are in S and m
Let B be the Beatty sequence of r. Then a floor-sum sequence of r is a subsequence of B if and only if a(1) and a(2) are terms of B. Thus, A182669 is a subsequence of the lower Wythoff sequence, A000201.

Examples

			a(3)=floor(r+3r)=6.
		

Crossrefs

Programs

  • PARI
    lista(nn) = my(S=[1, 3], r=(1+sqrt(5))/2, new, k); while(1, new=[]; for(m=1, #S, for(n=m+1, #S, k=floor(r*(S[m]+S[n])); if(k<=nn, new=setunion(new,[k])))); if(S==setunion(S,new), return(S)); S=setunion(S,new)) \\ Iain Fox, Apr 25 2019
  • QBasic
    r=(1+5^(1/2))/2: s(1)=1: s(2)=3: s(5)=6
    For h=2 to 200: c(h)=h+c(h-1): next h
    For h=1 to 100: c=c(h): d=0
      For i=1 to h+1: d=d+1: s(c+d)=int(s(i)+s(h+2)*r)
      Next i
    Next h
    For i=1 to 1000: for j=i+1 to 1001
    if s(i)>=s(j) then swap s(i),s(j)
    next j,i
    For i=1 to 120: if s(i+1)<>s(i) then print s(i);
    next i
    

Extensions

139 (generated by m=22, n=64) added by R. J. Mathar, Nov 28 2010