VOOZH about

URL: https://oeis.org/A158871

⇱ A158871 - OEIS

login
A158871
Those positive integers m where (the number of integers k, 0 <= k <= m, where the binomial coefficient C(m,k) is divisible by m) > (the number of positive integers <= m and coprime to m).
1
1, 10, 12, 18, 20, 21, 22, 24, 26, 28, 30, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 50, 52, 54, 55, 56, 57, 58, 60, 63, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 82, 84, 85, 86, 87, 88, 90, 92, 93, 94, 96, 98, 99, 100, 102, 104, 105, 106, 108, 110, 111, 112, 114
OFFSET
1,2
COMMENTS
Also numbers m such that A020475(m) > A000010(m).
A020475(n) = the number of integers k, 0 <= k <= n, where the binomial coefficient C(n,k) is divisible by n.
A000010(n) = the number of positive integers <= n and coprime to n.
A020475(n) >= A000010(n) for all positive integers n.
LINKS
EXAMPLE
From David A. Corneth, May 04 2025: (Start)
12 is in the sequence since 12 | binomial(12, k) for k in {1, 5, 6, 7, 11}. Those are five numbers. A000010(12) = 4 and 5 > 4.
16 is not in the sequence as 16 | binomial(16, k) for k in {1, 3, 5, 7, 9, 11, 13, 15}. Those are 8 numbers. A000010(16) = 8. Those are the same numbers. (End)
CROSSREFS
Sequence in context: A270819 A031183 A265043 * A359074 A247626 A247627
KEYWORD
nonn
AUTHOR
Leroy Quet, Mar 28 2009
EXTENSIONS
Extended by R. J. Mathar, May 21 2009
STATUS
approved