A201208 - OEIS

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A201208

One 1, two 2's, three 1's, four 2's, five 1's, ...

2

1, 2, 2, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..105.

FORMULA

a(n) = A057212(n) + 1. - T. D. Noe, Nov 28 2011

EXAMPLE

May be written as a triangle:

1

2 2

1 1 1

2 2 2 2

1 1 1 1 1

2 2 2 2 2 2

1 1 1 1 1 1 1

Row sums are A022998(n+1).

MATHEMATICA

ReplaceAll[ColumnForm[Table[Mod[k, 2], {k, 12}, {n, k}], Center], 0 -> 2] (* Alonso del Arte, Nov 28 2011 *)

PROG

(Haskell)

a201208 n = a201208_list !! (n-1)

a201208_list = concat $ zipWith ($) (map replicate [1..]) a000034_list

-- Reinhard Zumkeller, Dec 02 2011

CROSSREFS

Cf. A057212, A022998.

Sequence in context: A228825 A324381 A331383 * A006513 A105224 A261627

Adjacent sequences: A201205 A201206 A201207 * A201209 A201210 A201211

KEYWORD

nonn,tabl,easy

AUTHOR

Paul Curtz, Nov 28 2011

EXTENSIONS

Edited by N. J. A. Sloane, Dec 02 2011

STATUS

approved