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A057212 n-th run has length n. 7
0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

T(n,k) = 1 - n mod 2, 1 <= k <= n. [Reinhard Zumkeller, Mar 18 2011]

REFERENCES

K. H. Rosen, Discrete Mathematics and its Applications, 1999, fourth edition, page 79, exercise 10 (g).

LINKS

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

FORMULA

a(n)=A003056(n) mod 2 so as a square array T(n, k)=n+k mod 2 - Henry Bottomley, Mar 22 2001

a(n) = (1+(-1)^A002024(n))/2, where A002024(n)=round(sqrt(2*n)). - Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Feb 23 2003

a(n)=A163334(n) mod 2 = A163336(n) mod 2 = A163357(n) mod 2 = A163359(n) mod 2, i.e. the array gives the parity of elements at the successive antidiagonals (alternating between 0 and 1) of square arrays constructed from ANY Hilbert curve starting from zero located at the top left corner of a square grid (and using only N,E,S,W steps of length one). - Antti Karttunen, Oct 22 2012

MAPLE

A002024 := n->round(sqrt(2*n)):A057212 := n->(1+(-1)^A002024(n))/2;

PROG

(Haskell)

a057212 n = a057212_list !! (n-1)

a057212_list = concat $ zipWith ($) (map replicate [1..]) a000035_list

-- Reinhard Zumkeller, Mar 18 2011

CROSSREFS

Cf. A057211.

As a simple triangular or square array virtually the only sequences which appear are A000004, A000012 and A000035. Cf. A060510.

Sequence in context: A030301 A093692 A105384 * A023959 A076182 A010058

Adjacent sequences:  A057209 A057210 A057211 * A057213 A057214 A057215

KEYWORD

easy,nonn,tabl

AUTHOR

Ben Tyner (tyner(AT)phys.ufl.edu), Sep 27 2000

STATUS

approved

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Last modified October 22 23:18 EDT 2018. Contains 316518 sequences. (Running on oeis4.)