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A162917 Numbers n which are not in A161983. 5

%I #25 Dec 11 2019 07:18:04

%S 1,2,6,7,8,9,15,16,17,18,19,20,28,29,30,31,32,33,34,35,45,46,47,48,49,

%T 50,51,52,53,54,66,67,68,69,70,71,72,73,74,75,76,77,91,92,93,94,95,96,

%U 97,98,99,100,101,102,103,104,120,121,122,123,124,125,126,127,128

%N Numbers n which are not in A161983.

%C They have a block structure: A000384(n) is followed by the next n integers.

%C Numbers k with the property that the largest Dyck path of the symmetric representation of sigma(k) has a central peak. (Cf. A237593.) - _Omar E. Pol_, Aug 28 2018

%C Union of nonzero terms of A000384 and A317303. - _Omar E. Pol_, Aug 29 2018

%F A000027 \ A161983.

%e From _Omar E. Pol_, Aug 28 2018: (Start)

%e Also, written as an irregular triangle in which the row lengths are the positive even numbers, the sequence begins:

%e 1, 2;

%e 6, 7, 8, 9;

%e 15, 16, 17, 18, 19, 20;

%e 28, 29, 30, 31, 32, 33, 34, 35;

%e 45, 46, 47, 48, 49, 50, 51, 52, 53, 54;

%e 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77;

%e 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104;

%e ...

%e Row sums give A035328, n >= 1.

%e Column 1 gives A000384, n >= 1.

%e Column 2 gives A130883, n >= 1.

%e Right border gives the positive terms of A014107, also the odd-indexed terms of A000096.

%e (End)

%Y Complement of A161983.

%Y Cf. A000096, A000384, A014107, A035328, A130883, A237593, A317303.

%K nonn,tabf

%O 1,2

%A _Juri-Stepan Gerasimov_, Jul 17 2009

%E 119 removed by _R. J. Mathar_, Jul 19 2009

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Last modified April 18 20:21 EDT 2024. Contains 371781 sequences. (Running on oeis4.)