A378729 Characteristic function of the primitive practical numbers as a subsequence of the practical numbers.

1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1

Offset

1,0

Comments

a(n) = 1 indicates that the practical number A005153(n) is also primitive.

Links

Table of n, a(n) for n=1..120.

Example

a(9) = 1 because A005153(9) = 20 and 20 is primitive practical.

Mathematica

plst=Last/@ReadList["https://oeis.org/A005153/b005153.txt", {Number, Number}]; pplst=Last/@ReadList["https://oeis.org/A267124/b267124.txt", {Number, Number}]; getpplst[n_] := Module[{}, Select[pplst, # <= n &]]; Table[lst=getpplst[plst[[n]]]; If[MemberQ[lst, plst[[n]]], 1, 0], {n, 1, 200}]

Crossrefs

Cf. A005153, A267124.

Sequence in context: A379111 A262683 A359816 * A321083 A154269 A036987

Adjacent sequences: A378726 A378727 A378728 * A378730 A378731 A378732

Keyword

nonn

Author

Frank M Jackson, Dec 06 2024

Status

approved