A195437 Triangle formed by: 1 even, 2 odd, 3 even, 4 odd... starting with 2.

2, 5, 7, 10, 12, 14, 17, 19, 21, 23, 26, 28, 30, 32, 34, 37, 39, 41, 43, 45, 47, 50, 52, 54, 56, 58, 60, 62, 65, 67, 69, 71, 73, 75, 77, 79, 82, 84, 86, 88, 90, 92, 94, 96, 98, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 122, 124, 126, 128, 130, 132

Offset: 0

Author

Reinhard Zumkeller, Oct 12 2011

Keywords

• nonn
• tabl

Comments

A127366(T(n,k)) mod 2 = 1;

T(n,k) mod 2 + A000196(T(n,k)) mod 2 = 1;

complement of A133280.

Links

• Reinhard Zumkeller, Rows n=0..100 of triangle, flattened

Crossrefs

Cf. A002522 (left edge), A008865 (right edge), A011379 (row sums), A002939 (central terms).

Programs

Haskell

a195437 n k = a195437_tabl !! n !! k
a195437_tabl = tail $ g 1 1 [0..] where
   g m j xs = (filter ((== m) . (`mod` 2)) ys) : g (1 - m) (j + 2) xs'
     where (ys,xs') = splitAt j xs
b195437 = bFile' "A195437" (concat $ take 101 a195437_tabl) 0
-- Reinhard Zumkeller, Nov 23 2011 (fixed), Oct 12 2011

Mathematica

p[n_,k_]:=NestList[#+2&,n,k-1]; Module[{nn=6,ev,od},ev=p@@@Partition[Riffle[Table[ 4n^2-4n+2,{n,nn}],Range[ 1,2nn,2]],2];od=p@@@Partition[Riffle[Table[4n^2+1,{n,nn}],Range[ 2,2nn+1,2]],2];Sort[Flatten[Join[ev,od]]]] (* Harvey P. Dale, Aug 27 2023 *)