A372095 a(n) = 3-adic valuation of A008336(3*n).

0, 1, 0, 2, 1, 2, 0, 1, 2, 5, 4, 5, 3, 4, 3, 1, 2, 3, 0, 1, 0, 2, 1, 2, 0, 1, 0, 4, 3, 4, 2, 1, 2, 0, 1, 2, 5, 4, 3, 5, 6, 7, 5, 6, 5, 2, 3, 4, 6, 5, 4, 6, 5, 6, 2, 1, 2, 0, 1, 2, 0, 1, 0, 3, 4, 5, 3, 4, 3, 5, 4, 5, 2, 3, 2, 0, 1, 0, 2, 3, 4, 9, 8, 9, 7, 8, 7

Offset: 1

Author

Michael De Vlieger, Jun 02 2024

Keywords

• nonn
• easy

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A007949, A008336, A371908, A372840.

Programs

Mathematica

k = 2; nn = 360; p[_] := 0; r = 0; q = Prime[k];
{0}~Join~Reap[
   Do[If[AnyTrue[#, p[#1] < #2 & @@ # &],
        Map[p[#1] += #2 & @@ # &, #],
        Map[p[#1] -= #2 & @@ # &, #] ] &@
        Map[{PrimePi[#1], #2} & @@ # &, FactorInteger[n]];
      If[Divisible[n, q], Sow[p[k] ] ], {n, nn}] ][[-1, 1]]

Formula

a(n) = A007949(A008336(3*n)).