OFFSET
0,3
EXAMPLE
a(0) = #{0} = 1;
a(1) = #{1} = 1;
a(2) = #{1, 3} = 2;
a(3) = #{2, 8} = 2;
a(4) = #{3, 5, 21} = 3;
a(5) = #{5, 13, 55} = 3;
a(6) = #{8, 34, 144} = 3;
a(7) = #{13, 55, 89, 377} = 4;
a(8) = #{21, 233, 987} = 3;
a(9) = #{34, 610, 2584} = 3;
a(10) = #{55, 89, 377, 1597, 6765} = 5;
a(11) = #{89, 377, 4181, 17711} = 4;
a(12) = #{144, 10946, 46368} = 3;
a(13) = #{233, 1597, 28657, 121393} = 4;
a(14) = #{377, 987, 1597, 6765, 75025, 317811} = 6;
a(15) = #{610, 10946, 196418, 832040} = 4;
a(16) = #{987, 4181, 6765, 514229, 2178309} = 5.
PROG
(Haskell)
a231335 = length . filter ((== 1) . a010056) . a231330_row
(PARI) isfib(n) = my(k=n^2); k+=(k+1)<<2; issquare(k) || issquare(k-8);
vf(v) = #select(isfib, Set(v));
lista(nn) = my(va=[0], vb=[1]); print1(vf(va), ", "); print1(vf(vb), ", "); for (n=2, nn, v = vector(2^(n-1), k, j=(k+1)\2; i=(j+1)\2; y=vb[j]; x=va[i]; if (k%2, y+x, 3*y-x)); print1(vf(v), ", "); va = vb; vb = v; ); \\ Michel Marcus, Sep 23 2023
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Reinhard Zumkeller, Nov 07 2013
EXTENSIONS
a(19)-a(25) from Michel Marcus, Sep 23 2023
STATUS
approved