

A244216


Numbers n that are at least twice the size the largest Catalan number less than or equal to n.


4



4, 10, 11, 12, 13, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 264
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OFFSET

1,1


COMMENTS

Equally: Numbers k such that if m is the largest Catalan number <= k [= A081290(k)], then k >= 2*m.
Numbers k such that the Greedy Catalan Base representation of k (cf. A014418) starts with digit 2 or 3.


LINKS



EXAMPLE

4 is present, as the largest Catalan number (A000108(k), here C(k)) less than or equal to 4 is C(2) = 2, and 4 >= 2*2.
5 is not present, as the largest Catalan number <= 5 is C(3) = 5, and 5 < 2*5.
10 is present, as the largest Catalan number <= 10 is C(3) = 5, and 10 >= 2*5.
11 is present, as the largest Catalan number <= 11 is C(3) = 5, and 11 >= 2*5.
27 is not present, as the largest Catalan number <= 27 is C(4) = 14, and 27 < 2*14.
28 is present, as the largest Catalan number <= 28 is C(4) = 14, and 28 >= 2*14.


PROG

(Scheme, with Antti Karttunen's IntSeqlibrary, two alternative definitions)
(define A244216 (MATCHINGPOS 1 1 (lambda (k) (>= k (* 2 (A081290 k))))))


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



