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 A291306 #11 Jan 16 2025 02:38:35
%S A291306 0,0,2,4,0,6,6,6,8,10,6,12,12,12,14,16,12,18,18,18,20,22,18,24,24,24,
%T A291306 26,28,24,30,30,30,32,34,30,36,36,36,38,40,36,42,42,42,44,46,42,48,48,
%U A291306 48,50,52,48,54,54,54,56,58,54,60,60,60,62,64,60,66,66,66,68
%N A291306 The arithmetic function v_6(n,1).
%D A291306 J. Butterworth, Examining the arithmetic function v_g(n,h). Research Papers in Mathematics, B. Bajnok, ed., Gettysburg College, Vol. 8 (2008).
%H A291306 Bela Bajnok, <a href="https://arxiv.org/abs/1705.07444">Additive Combinatorics: A Menu of Research Problems</a>, arXiv:1705.07444 [math.NT], May 2017. See Table in Section 1.6.1.
%F A291306 a(n) = n - gcd(n,6) = n - A089128(n). - _Ridouane Oudra_, Dec 15 2024
%F A291306 Sum_{n>=7} (-1)^n/a(n) = Pi/(6*sqrt(3)) - 1/4. - _Amiram Eldar_, Jan 15 2025
%p A291306 seq(n-gcd(n,6), n=2..100); # _Ridouane Oudra_, Dec 15 2024
%t A291306 v[g_, n_, h_] := (d = Divisors[n]; Max[(Floor[(d - 1 - GCD[d, g])/h] + 1)*n/d]); Table[v[6, n, 1], {n, 2, 70}]
%Y A291306 Cf. A289435, A289436, A289437, A289438, A289439, A289440, A289441.
%Y A291306 Cf. A089128.
%K A291306 nonn
%O A291306 2,3
%A A291306 _Robert Price_, Aug 21 2017