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.

A254714 Numbers k such that the area of a circle of radius k is closer to an integer than the area of any circle whose radius is a smaller positive integer k.

Original entry on oeis.org

1, 6, 7, 8, 28, 85, 113, 198, 267, 659, 1014, 10224, 13451, 537766, 925036, 1693817, 1803181, 2053555, 11518526, 41877989, 66797547, 90328940, 105345415, 343594795, 654075889, 934979323, 1061368874
Offset: 1

Views

Author

Kival Ngaokrajang, Feb 06 2015

Keywords

Comments

Inspired by A067561.

Examples

			k   c=Pi*k^2   round(c)   c-round(c)  e=abs(c-round(c))
1    3.14159...    3      0.14159...     0.14159...
2   12.56637...   13     -0.43362...     0.43362...
3   28.27433...   28      0.27433...     0.27433...
4   50.26548...   50      0.26548...     0.26548...
5   78.53981...   79     -0.46018...     0.46018...
6  113.09733...  113      0.09733...     0.09733...
7  153.93804...  154     -0.06195...     0.06195...
...
a(1) = 1.
2, 3, 4 and 5 are not in the sequence, because their absolute errors e are greater than that of a(1).
6 is in the sequence, because its absolute error e is less than that of a(1), therefore a(2) = 6.
7 is in the sequence, because its absolute error e is less than that of a(2), therefore a(3) = 7.
...
		

Crossrefs

Cf. A067561.

Programs

  • PARI
    {m=1;for(n=1,10^10,c=Pi*n^2;e=abs(c-round(c));if(e