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A375999
Narayana numbers (A001263), sorted, duplicates removed.
3
1, 3, 6, 10, 15, 20, 21, 28, 36, 45, 50, 55, 66, 78, 91, 105, 120, 136, 153, 171, 175, 190, 196, 210, 231, 253, 276, 300, 325, 336, 351, 378, 406, 435, 465, 490, 496, 528, 540, 561, 595, 630, 666, 703, 741, 780, 820, 825, 861, 903, 946, 990, 1035, 1081, 1128
OFFSET
1,2
LINKS
Pontus von Brömssen, Table of n, a(n) for n = 1..10000
PROG
(Python)
from bisect import insort
from itertools import islice
def A375999_generator():
yield 1
nkN_list = [(3, 2, 3)] # List of triples (n, k, A001263(n, k)), sorted by the last element.
while 1:
N0 = nkN_list[0][2]
yield N0
while 1:
n, k, N = nkN_list[0]
if N > N0: break
del nkN_list[0]
insort(nkN_list, (n+1, k, n*(n+1)*N//((n-k+1)*(n-k+2))), key=lambda x:x[2])
if n == 2*k-1:
insort(nkN_list, (n+2, k+1, 4*n*(n+2)*N//(k+1)**2), key=lambda x:x[2])
def A375999_list(nmax):
return list(islice(A375999_generator(), nmax))
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved