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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
OFFSET
0
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
Sequence in context: A356556 A330037 A255817 * A179829 A172486 A288223
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