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.

A080387 Numbers k such that there are exactly 10 numbers j for which binomial(k, floor(k/2)) / binomial(k,j) is an integer, i.e., A080383(k) = 10.

This page as a plain text file.
%I A080387 #18 Sep 10 2019 03:03:14
%S A080387 13,31,41,57,85,91,133,155,177,183,209,221,253,281,307,313,341,375,
%T A080387 381,409,419,441,457,463,477,481,533,553,599,617,625,631,645,651,661,
%U A080387 691,737,757,829,841,859,871,881,885,901,919,929,937,953,967,987,993
%N A080387 Numbers k such that there are exactly 10 numbers j for which binomial(k, floor(k/2)) / binomial(k,j) is an integer, i.e., A080383(k) = 10.
%H A080387 Vaclav Kotesovec, <a href="/A080387/b080387.txt">Table of n, a(n) for n = 1..5113</a>
%e A080387 For n=13, the central binomial coefficient (C(13,6) = 1716) is divisible by 10 binomial coefficients C(13,j); the 4 nondivisible cases are C(13,4), C(13,5), C(13,8), and C(13,9).
%Y A080387 Cf. A327430, A080384, A080385, A080386, A327431.
%Y A080387 Cf. A001405, A057977.
%K A080387 nonn
%O A080387 1,1
%A A080387 _Labos Elemer_, Mar 12 2003