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.

A254608 a(n) is the smallest number such that A254606(a(n)) = n.

Original entry on oeis.org

1, 2, 9, 14, 27, 26, 34, 63, 64, 53, 89, 115, 88, 165, 101, 116, 132, 292, 149, 185, 166, 225, 271, 205, 270, 318, 247, 397, 294, 293, 319, 370, 371, 344, 399, 398, 427, 691, 489, 488, 553, 552, 520, 655, 658, 620, 622, 769, 621, 693, 656, 731, 851, 810, 732
Offset: 0

Views

Author

Lei Zhou, Feb 02 2015

Keywords

Examples

			A254606(1)=0, so a(0)=1;
A254606(2)=1, so a(1)=2;
A254606(m)<2 for all m<9, and A254606(9)=2, so a(2)=9.
		

Crossrefs

Cf. A254606.

Programs

  • Mathematica
    NumDiff[n1_, n2_] :=  Module[{c1 = n1, c2 = n2}, If[c1 < c2, c1 = c1 + c2; c2 = c1 - c2; c1 = c1 - c2];
      k = Floor[c1/c2]; a1 = c1 - k*c2; If[a1 == 0, a2 = 0, a2 = (k + 1) c2 - c1]; Return[Min[a1, a2]]];
    a = {1}; n = 0; p1 = 2; p2 = 1; lb = 0; While[lb < 100, n++; p2 = NextPrime[p2]; If[p2 > p1, p1 = p2; p2 = 2];
    d = NumDiff[p1, p2]; While[l = Length[a]; l <= d, AppendTo[a, 0]]; If[a[[d + 1]] == 0, a[[d + 1]] = n; ps = Position[a, 0]; If[Length[ps] == 0, b = a, ps1 = ps[[1]][[1]]; b = Take[a, ps1 - 1]]; lb = Length[b]]]; b