cp's OEIS Frontend

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.

A359423 The least common multiple of the arithmetic derivative and the primorial base exp-function.

Original entry on oeis.org

0, 0, 3, 6, 36, 18, 5, 10, 60, 30, 315, 90, 400, 50, 225, 600, 7200, 450, 2625, 250, 3000, 750, 14625, 2250, 27500, 1250, 1875, 33750, 180000, 11250, 217, 14, 1680, 42, 1197, 252, 420, 70, 105, 1680, 21420, 630, 7175, 350, 8400, 13650, 1575, 3150, 14000, 1750, 7875, 10500, 63000, 15750, 354375, 70000
Offset: 0

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Author

Antti Karttunen, Jan 02 2023

Keywords

Examples

			For n=32, we have A003415(32) = 80 and A276086(32) = 21, therefore a(32) = lcm(80,21) = 1680.
For n=39, we have A003415(39) = 16 and A276086(39) = 210, therefore a(39) = lcm(16,210) = 1680.
		

Crossrefs

Cf. A003415, A276086, A327858, A358669, A359424 [= a(n) mod 60].
Cf. A016825 (positions of odd terms), A042965 (of even terms), A327864 (of multiples of 4).

Programs

  • PARI
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A359423(n) = lcm(A003415(n), A276086(n));

Formula

a(n) = lcm(A003415(n), A276086(n)).
a(n) = A358669(n) / A327858(n).