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 A285426 Numbers n such that at least two consecutive elements of the n-th row of A237591 are in increasing order. 1
 14, 20, 25, 27, 33, 34, 35, 39, 42, 43, 44, 49, 50, 52, 53, 54, 56, 60, 61, 62, 63, 64, 65, 68, 69, 72, 73, 74, 75, 76, 77, 81, 82, 83, 85, 86, 87, 88, 89, 90, 91, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 121, 122, 123, 124, 125, 126, 127, 128 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS In other words: numbers n such that the elements of the n-th row of A237591 are not in nonincreasing order. Note that the n-th row of A237591 is also the first half of the associated Dyck path of A237593. LINKS EXAMPLE 14 is in the sequence because the elements of the 14th row of A237591 are 8, 3, 1, 2, and they are not in nonincreasing order (note that the last two element are in increasing order). PROG (Python) import math from sympy import sqrt def T(n, k): return int(math.ceil((n + 1)/k - (k + 1)/2)) - int(math.ceil((n + 1)/(k + 1) - (k + 2)/2)) def isok(n):     l = [T(n, k) for k in range(1, int(math.floor((sqrt(8*n + 1) - 1)/2)) + 1)]     return any(l[i + 1] > l[i] for i in range(len(l) - 1)) print([n for n in range(1, 151) if isok(n)]) # Indranil Ghosh, Apr 20 2017 CROSSREFS Complement of A285356. Cf. A196020, A235791, A236104, A237048, A237591, A237593, A245092. Sequence in context: A087678 A144585 A186193 * A108874 A063848 A110968 Adjacent sequences:  A285423 A285424 A285425 * A285427 A285428 A285429 KEYWORD nonn AUTHOR Omar E. Pol, Apr 18 2017 STATUS approved

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Last modified August 2 16:58 EDT 2021. Contains 346428 sequences. (Running on oeis4.)