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.

A281533 Numbers such that A279967(n) = 0.

Original entry on oeis.org

17, 23, 47, 57, 93, 107, 155, 173, 233, 255, 327, 353, 437, 467, 563, 597, 677, 705, 743, 863, 905, 1037, 1083, 1187, 1227, 1277, 1433, 1487, 1607, 1655, 1713, 1893, 1955, 2027, 2095, 2147, 2213, 2293, 2357, 2417, 2467, 2487, 2503, 2703, 2719, 2777, 2861, 2993, 3005, 3083, 3251
Offset: 1

Views

Author

Hartmut F. W. Hoft, Jan 23 2017

Keywords

Comments

This sequence is neither a subset nor a superset of sequence A278436 since 155 and 817 are in one, but not the other, respectively.

Examples

			Number 155 = 5*31, equivalent to array position (17, 2), is in the sequence since all prior numbers in column 1 are even as are those in column 2, except 9 which is not a factor of 155.
		

Crossrefs

Programs

  • Mathematica
    (* support functions are in A279967*)
    a281533[k_] := Module[{ut=upperTriangle[k], ms=Table[" ", {i, 1, k}, {j, 1, k}], h, pos, val, seqL={}}, ms[[1, 1]]=1; For[h=2, h<=Length[ut], h++, pos=ut[[h]]; val=Apply[Plus, Select[Map[ms[[Apply[Sequence, #]]]&, priorPos[pos]], #!=0 && Mod[seqPos[pos], #]==0&]]; If[val==0,AppendTo[seqL, val]]; ms[[Apply[Sequence, pos]]]=val]; seqL]
    a281533[81] (* data *)