A071674 Sequence A071673 reduced modulo 2.

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

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