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A133280
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Triangle formed by: 1 even, 2 odd, 3 even, 4 odd... starting with zero.
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3
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0, 1, 3, 4, 6, 8, 9, 11, 13, 15, 16, 18, 20, 22, 24, 25, 27, 29, 31, 33, 35, 36, 38, 40, 42, 44, 46, 48, 49, 51, 53, 55, 57, 59, 61, 63, 64, 66, 68, 70, 72, 74, 76, 78, 80, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| This sequence is related to the Connell sequence (A001614).
First member of every row is a square (A000290).
A127366(T(n,k)) mod 2 = 0 or equal parity of T(n,k) and A000196(T(n,k)); complement of A195437. [Reinhard Zumkeller, Oct 12 2011]
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LINKS
| Reinhard Zumkeller, Rows n=0..100 of triangle, flattened
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EXAMPLE
| Triangle begins:
0
1, 3
4, 6, 8
9, 11, 13, 15
16, 18, 20, 22, 24
25, 27, 29, 31, 33, 35
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PROG
| (Haskell)
a133280 n k = a133280_tabl !! n !! k
a133280_tabl = f 0 1 [0..] where
f m j xs = (filter ((== m) . (`mod` 2)) ys) : f (1 - m) (j + 2) xs'
where (ys, xs') = splitAt j xs
b133280 = bFile' "A133280" (concat $ take 101 a133280_tabl) 0
-- Reinhard Zumkeller, Oct 12 2011
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CROSSREFS
| Cf. A000290, A001614, A005563.
Cf. A045991 (row sums). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 20 2009]
Sequence in context: A047206 A187474 A081031 * A138097 A193732 A000592
Adjacent sequences: A133277 A133278 A133279 * A133281 A133282 A133283
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KEYWORD
| easy,nonn,tabl
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AUTHOR
| Omar E. Pol (info(AT)polprimos.com), Aug 27 2008
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