A183039 a(n) = A051064(n)*3^A051064(n) where A051064(n) equals the 3-adic valuation of 3n.

3, 3, 18, 3, 3, 18, 3, 3, 81, 3, 3, 18, 3, 3, 18, 3, 3, 81, 3, 3, 18, 3, 3, 18, 3, 3, 324, 3, 3, 18, 3, 3, 18, 3, 3, 81, 3, 3, 18, 3, 3, 18, 3, 3, 81, 3, 3, 18, 3, 3, 18, 3, 3, 324, 3, 3, 18, 3, 3, 18, 3, 3, 81, 3, 3, 18, 3, 3, 18, 3, 3, 81, 3, 3, 18, 3, 3, 18, 3, 3, 1215, 3, 3, 18, 3, 3, 18, 3, 3, 81

Offset: 1

Author

Paul D. Hanna, Dec 19 2010

Keywords

• nonn

Comments

3^A051064(n) exactly divides 3n.

Examples

			L.g.f.: A(x) = 3*x + 3*x^2/2 + 18*x^3/3 + 3*x^4/4 + 3*x^5/5 + 18*x^6/6 + 3*x^7/7 + 3*x^8/8 + 81*x^9/9 + 3*x^10/10 + 3*x^11/11 + 18*x^12/12 +...
The g.f. of A183038 begins:
exp(A(x)) = 1 + 3*x + 6*x^2 + 15*x^3 + 30*x^4 + 51*x^5 + 93*x^6 +...
		

Links

• Antti Karttunen, Table of n, a(n) for n = 1..59049

Crossrefs

Cf. A183038, A183037.

Programs

PARI

{a(n)=valuation(3*n,3)*3^valuation(3*n,3)}

Formula

Logarithmic derivative of A183038.