A192687 Male-female differences: a(n) = A005378(n) - A005379(n).

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

Offset

0

Comments

0 <= a(n) <= 1;

for n > 0: a(n) = A010056(n-1), a(A001690(n)-1) = 0, a(A000071(n)) = 1.

References

Hofstadter, "Goedel, Escher, Bach", p. 137.

Links

Charles R Greathouse IV, Table of n, a(n) for n = 0..10000

Eric Weisstein's World of Mathematics, Hofstadter Male-Female Sequences.

Index entries for Hofstadter-type sequences

Index entries for sequences from "Goedel, Escher, Bach"

Prog

(Haskell)
a192687 n = a192687_list !! n
a192687_list = zipWith (-) females males where
   females = 1 : zipWith (-) [1..] (map (males !!) females)
   males = 0 : zipWith (-) [1..] (map (females !!) males)
(PARI) a(n)=my(k=(n+1)^2); k+=(k+1)<<2; issquare(k) || issquare(k-8) \\ Charles R Greathouse IV, Nov 07 2014

Crossrefs

Cf. A000071, A001690, A005378, A005379, A010056, A104162.

Sequence in context: A093709 A079295 A088025 * A189141 A082416 A093996

Adjacent sequences: A192684 A192685 A192686 * A192688 A192689 A192690

Keyword

nonn,easy

Author

Reinhard Zumkeller, Jul 12 2011

Status

approved