login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A048569 Values of k for which the number of divisors of the central binomial coefficient C(k, floor(k/2)) exceeds the number of divisors of all other binomial coefficients C(k,j). 2
1, 2, 3, 4, 5, 6, 10, 13, 14, 15, 16, 22, 26, 29, 30, 37, 38, 39, 40, 46, 47, 48, 57, 58, 85, 86, 87, 93, 94, 95, 97, 98, 106, 107, 122, 123, 124, 125, 147, 148, 149, 150, 157, 158, 159, 178, 194, 206, 214, 219, 220, 226, 230, 232, 247, 278, 283, 284, 285, 286, 316 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

k is in the sequence if the number of divisors of the central binomial coefficient C(k, floor(k/2)) (i.e., C(k, k/2) for even k, and C(k,(k-1)/2) = C(k,(k+1)/2) for odd k) is greater than the number of divisors of C(k, j) for all other values of j.

LINKS

Table of n, a(n) for n=1..61.

EXAMPLE

If n=10 and k=0..10 then A000005(binomial(10,k)) = 1, 4, 6, 16, 16, 18, 16, 16, 6, 4, 1. The maximum value of A000005(binomial(10,k)), i.e., 18 occurs only at k=5, the central coefficient. Thus 10 is in this sequence.

CROSSREFS

Cf. A000005, A001405, A048274, A034974, A048570.

Sequence in context: A018266 A128945 A318533 * A033085 A332320 A006543

Adjacent sequences:  A048566 A048567 A048568 * A048570 A048571 A048572

KEYWORD

nonn

AUTHOR

Labos Elemer

EXTENSIONS

Edited by Jon E. Schoenfield, May 19 2018

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 5 09:46 EDT 2020. Contains 334829 sequences. (Running on oeis4.)