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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A308972 Least k > 0 such that A114561(k) == A114561(k+1) mod n.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 2, 1, 2, 3, 1, 2, 1, 2, 2, 2, 1, 2, 2, 1, 3, 4, 2, 3, 2, 2, 1, 2, 2, 3, 2, 3, 2, 2, 1, 2, 2, 2, 2, 3, 1, 2, 3, 2, 4, 5, 2, 2, 3, 2, 2, 3, 2, 3, 2, 2, 2, 3, 2, 3, 3, 1, 2, 2, 3, 4, 2, 4, 2, 3, 2, 2, 2, 3, 2, 3, 2, 3, 2, 3, 3, 4, 1, 2, 2, 2
Offset: 1

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Author

Jinyuan Wang, Aug 30 2019

Keywords

Comments

A114561(k+1) - A114561(k) is the largest n such that a(n) = k.

Examples

			4, 4^4, 4^4^4, ... mod 8 equal 4, 0, 0, ..., so A114561(k) mod 8 = 0 for all k >= 2, hence a(8) = 2.
		

Crossrefs

Programs

  • PARI
    a(n) = {c=0; k=1; x=0; d=n; while(k==1, z=x++; y=0; b=1; while(z>0, while(y++
    				

Formula

a(n) <= A003434(n).
a(n) <= a(A000010(n)) + 1. Proof: a(n) <= a(eulerphi(n)) + 1. Proof: If A114561(i) == b(i) mod eulerphi(n), 0 < b(i) <= eulerphi(n), then a(n) is the least k > 0 such that 2^b(k-1) == 2^b(k) mod n. Since A114561(a(eulerphi(n))) == A114561(a(eulerphi(n)) + 1), k <= a(A000010(n)) + 1.
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