A055087 - OEIS

A055087

Integers 0..n then 0..n then 0..n+1 then 0..n+1 etc.

0, 0, 0, 1, 0, 1, 0, 1, 2, 0, 1, 2, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 6, 0, 1, 2, 3, 4, 5, 6, 0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7, 8, 0, 1, 2, 3, 4, 5, 6, 7, 8, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1

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OFFSET

0,9

COMMENTS

Second column in the monotonic justified array of all positive generalized Fibonacci sequences (A160271). see also A199474. - Casey Mongoven, Nov 06 2011

Can also be seen as an irregular triangle with duplicated rows of A002262. - Reinhard Zumkeller, Jul 14 2015

LINKS

Reinhard Zumkeller, Rows n = 0..120 of triangle, flattened

Michael Somos, Sequences used for indexing triangular or square arrays

EXAMPLE

0; 0; 0,1; 0,1; 0,1,2; 0,1,2; 0,1,2,3; 0,1,2,3; ...

MATHEMATICA

With[{nn=10}, Flatten[Table[{Range[0, n], Range[0, n]}, {n, 0, nn}]]] (* Harvey P. Dale, May 30 2015 *)

PROG

(PARI) {a(n) = (1 + 4*n - sqr( floor( sqrt( 1 + 4*n)))) \ 4}

(Haskell)

import Data.List (transpose)