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.
%I A183039 #11 Jul 02 2024 14:43:35 %S A183039 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, %T A183039 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, %U A183039 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 %N A183039 a(n) = A051064(n)*3^A051064(n) where A051064(n) equals the 3-adic valuation of 3n. %C A183039 3^A051064(n) exactly divides 3n. %H A183039 Antti Karttunen, <a href="/A183039/b183039.txt">Table of n, a(n) for n = 1..59049</a> %F A183039 Logarithmic derivative of A183038. %e A183039 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 +... %e A183039 The g.f. of A183038 begins: %e A183039 exp(A(x)) = 1 + 3*x + 6*x^2 + 15*x^3 + 30*x^4 + 51*x^5 + 93*x^6 +... %o A183039 (PARI) {a(n)=valuation(3*n,3)*3^valuation(3*n,3)} %Y A183039 Cf. A183038, A183037. %K A183039 nonn %O A183039 1,1 %A A183039 _Paul D. Hanna_, Dec 19 2010