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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A048824 a(n) = least k such that A048823(n) = k.

Original entry on oeis.org

2, 3, 7, 23, 347, 1439, 10780559
Offset: 0

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Author

Christian G. Bower, May 15 1999

Keywords

Comments

a(6) > 1000000.
a(7) > 10^8, if it exists. - Don Reble, Apr 02 2002

Extensions

More terms from Don Reble, Apr 02 2002

A047988 Start with n and reach 2 by repeatedly either dividing by d where d <= the square root or by adding or subtracting 1. The division steps are free, but adding or subtracting 1 costs 1 point. a(n) is the smallest cost to reach 2.

Original entry on oeis.org

0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 2, 1, 1, 1, 1, 0, 1, 1, 1, 1, 2, 1, 1, 0, 1, 1, 1, 0, 1, 2, 1, 0, 1, 1, 2, 1, 1, 1, 1, 0, 1, 1, 1, 1, 2, 1, 1, 0, 1, 2, 1, 0, 1, 1, 1, 0, 1, 1, 2, 1, 1, 1, 1, 0, 1, 1, 1, 2, 1, 1, 1, 0, 1, 1, 1, 0, 1, 2, 2, 1, 2, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 2
Offset: 2

Views

Author

Thomas Kantke (bytes.more(AT)ibm.net)

Keywords

Examples

			From _David A. Corneth_, Jun 05 2020: (Start)
For n = 19 we get to 2 via
n := 19 - 1 = 2 (+1 point as we subtract 1 from n)
n := 18/3 = 6 (+0 point as we divide by a divisor)
n := 6/2 = 3 (+0 point, we divide by a divisor. we can't divide by 3 as 3 > sqrt(6)).
n := 3 - 1 = 2 (+1 point; steps end here; we have n = 2)
We earned 2 points in these steps. As this is the minimal number of points starting at n = 19, a(19) = 2. (End)
		

Crossrefs

Programs

Extensions

More terms from David W. Wilson
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