A071674 - OEIS

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A071674

Sequence A071673 reduced modulo 2.

3

0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0

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

OFFSET

0

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..10440 (rows 0..144 of the triangle, flattened)

Index entries for characteristic functions

FORMULA

a(n) = A000035(A071673(n)).

EXAMPLE

The first 15 rows of this irregular triangular table:

0,

1,

0, 0,

1, 1, 1,

1, 0, 0, 1,

0, 0, 1, 0, 0,

0, 1, 1, 1, 1, 0,

0, 1, 0, 1, 0, 1, 0,

0, 1, 0, 0, 0, 0, 1, 0,

1, 1, 0, 0, 1, 0, 0, 1, 1,

1, 0, 0, 0, 1, 1, 0, 0, 0, 1,

0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0,

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,

1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1,

0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0,

etc.

PROG

(PARI)

up_to = 10440;

A002260(n) = (n-binomial((sqrtint(8*n)+1)\2, 2)); \\ From A002260

A004736(n) = (1-n+(n=sqrtint(8*n)\/2)*(n+1)\2); \\ From A004736

A071673list(up_to) = { my(v=vector(1+up_to)); v[1] = 0; for(n=1, up_to, v[1+n] = 1 + v[A004736(n)] + v[A002260(n)]); (v); };

v071673 = A071673list(up_to);

A071673(n) = v071673[1+n];

A071674(n) = (A071673(n)%2); \\ Antti Karttunen, Aug 22 2021

CROSSREFS

Cf. A000035, A071673.

Sequence in context: A356556 A330037 A255817 * A179829 A172486 A288223

Adjacent sequences: A071671 A071672 A071673 * A071675 A071676 A071677

KEYWORD

nonn,tabf

AUTHOR

Antti Karttunen, May 30 2002

EXTENSIONS

Term a(0) = 0 prepended and the Example section added by Antti Karttunen, Aug 22 2021

STATUS

approved