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 A289440 The arithmetic function v_3(n,5). 113
 1, 0, 2, 1, 3, 2, 4, 2, 5, 2, 6, 3, 7, 3, 8, 4, 9, 4, 10, 6, 11, 5, 12, 5, 13, 6, 14, 6, 15, 6, 16, 6, 17, 10, 18, 8, 19, 9, 20, 8, 21, 9, 22, 10, 23, 10, 24, 14, 25, 12, 26, 11, 27, 11, 28, 12, 29, 12, 30, 12, 31, 18, 32, 15, 33, 14, 34, 15, 35 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,3 REFERENCES J. Butterworth, Examining the arithmetic function v_g(n,h). Research Papers in Mathematics, B. Bajnok, ed., Gettysburg College, Vol. 8 (2008). LINKS Bela Bajnok, Additive Combinatorics: A Menu of Research Problems, arXiv:1705.07444 [math.NT], May 2017. See Table in Section 1.6.1. MAPLE a:= n-> n*max(seq((floor((d-1-igcd(d, 3))/5)+1)         /d, d=numtheory[divisors](n))): seq(a(n), n=2..100);  # Alois P. Heinz, Jul 07 2017 MATHEMATICA a[n_]:=n*Max[Table[(Floor[(d - 1 - GCD[d, 3])/5] + 1)/d, {d, Divisors[n]}]]; Table[a[n], {n, 2, 100}] (* Indranil Ghosh, Jul 08 2017 *) PROG (PARI) v(g, n, h)={my(t=0); fordiv(n, d, t=max(t, ((d-1-gcd(d, g))\h + 1)*(n/d))); t} a(n)=v(3, n, 5); \\ Andrew Howroyd, Jul 07 2017 (Python) from sympy import divisors, floor, gcd def a(n): return n*max([(floor((d - 1 - gcd(d, 3))/5) + 1)/d for d in divisors(n)]) print([a(n) for n in range(2, 101)]) # Indranil Ghosh, Jul 08 2017 CROSSREFS Cf. A289439, A289441. Sequence in context: A204539 A302604 A214270 * A290636 A106466 A130722 Adjacent sequences:  A289437 A289438 A289439 * A289441 A289442 A289443 KEYWORD nonn AUTHOR N. J. A. Sloane, Jul 07 2017 EXTENSIONS a(41)-a(70) from Andrew Howroyd, Jul 07 2017 STATUS approved

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Last modified August 4 01:48 EDT 2020. Contains 336201 sequences. (Running on oeis4.)