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.

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A328382 a(n) = A276086(n) mod A003415(n), where A276086 is the primorial base exp-function and A003415 is the arithmetic derivative.

Original entry on oeis.org

0, 0, 1, 0, 0, 0, 3, 0, 3, 0, 9, 0, 3, 6, 1, 0, 20, 0, 15, 0, 7, 0, 9, 0, 0, 24, 25, 0, 7, 0, 21, 0, 6, 6, 35, 0, 0, 2, 43, 0, 11, 0, 45, 36, 0, 0, 91, 0, 15, 10, 35, 0, 1, 14, 61, 4, 5, 0, 49, 0, 15, 39, 57, 0, 1, 0, 15, 14, 22, 0, 133, 0, 9, 35, 65, 0, 19, 0, 71, 30, 42, 0, 121, 2, 30, 6, 105, 0, 97, 6, 69, 18, 0, 6, 83, 0, 63, 15, 35, 0, 21
Offset: 2

Views

Author

Antti Karttunen, Oct 15 2019

Keywords

Crossrefs

Cf. A003415, A276086, A327858, A358220, A358221 (positions of 0's), A358232 (of 1's), A358228 (of odd terms), A358229 (of even terms), A358227 (parity of terms).
Cf. also A328386.

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); };
    A328382(n) = (A276086(n)%A003415(n));

Formula

a(n) = A276086(n) mod A003415(n).
For n >= 2, gcd(a(n), A003415(n)) = A327858(n).

A358228 Numbers k such that A276086(k) mod A003415(k) is an odd number, where A003415 is the arithmetic derivative and A276086 is the primorial base exp-function.

Original entry on oeis.org

4, 8, 10, 12, 14, 16, 20, 22, 24, 28, 30, 32, 36, 40, 42, 44, 48, 50, 52, 54, 56, 58, 60, 62, 63, 64, 66, 68, 72, 74, 75, 76, 78, 80, 84, 88, 90, 92, 96, 98, 99, 100, 102, 104, 108, 110, 112, 114, 116, 120, 122, 124, 126, 128, 132, 136, 138, 140, 144, 148, 150, 152, 154, 156, 158, 160, 162, 164, 168, 171, 172, 176
Offset: 1

Views

Author

Antti Karttunen, Nov 25 2022

Keywords

Crossrefs

Complement: {1} U A358229.
Cf. A003415, A276086, A328382, A358228 (characteristic function), A358232 (subsequence).
Cf. also A358225.

Programs

Showing 1-2 of 2 results.