A286477 Ordinal transform of A032742, starting from its first term a(1) = 1.

1, 2, 3, 1, 4, 1, 5, 1, 2, 1, 6, 1, 7, 1, 2, 1, 8, 1, 9, 1, 2, 1, 10, 1, 3, 1, 2, 1, 11, 1, 12, 1, 2, 1, 3, 1, 13, 1, 2, 1, 14, 1, 15, 1, 2, 1, 16, 1, 4, 1, 2, 1, 17, 1, 3, 1, 2, 1, 18, 1, 19, 1, 2, 1, 3, 1, 20, 1, 2, 1, 21, 1, 22, 1, 2, 1, 4, 1, 23, 1, 2, 1, 24, 1, 3, 1, 2, 1, 25, 1, 4, 1, 2, 1, 3, 1, 26, 1, 2, 1, 27, 1, 28, 1, 2, 1, 29, 1, 30, 1, 2, 1, 31

Offset

1,2

Comments

If we instead apply the ordinal transform to A032742 starting from its second term a(2) = 1, the result seems to be a shifted version of A055396.

Links

Antti Karttunen, Table of n, a(n) for n = 1..10000

Mathematica

Function[{s, t}, ReplacePart[t, Flatten@ Map[MapIndexed[#1 -> First@ #2 &, #] &, Values@ s]]] @@ {PositionIndex@ #, ConstantArray[0, Length@ #]} & Table[n/FactorInteger[n][[1, 1]], {n, 113}] (* Michael De Vlieger, May 12 2017, Version 10 *)
b[_] = 0;
a[n_] := a[n] = With[{t = If[n == 1, 1, Divisors[n][[-2]]]}, b[t] = b[t]+1];
Array[a, 1000] (* Jean-François Alcover, Dec 24 2021 *)

Crossrefs

Cf. A032742, A055396.

Sequence in context: A226081 A109201 A002946 * A277230 A218534 A241773

Adjacent sequences: A286474 A286475 A286476 * A286478 A286479 A286480

Keyword

nonn

Author

Antti Karttunen, May 12 2017

Status

approved