A108115 Let B(x) = Sum_{i >= 0} A108336(i)*x^i; sequence gives coefficients of B(x)^2.

1, 2, 1, 2, 2, 2, 5, 2, 2, 2, 1, 2, 1, 2, 2, 2, 6, 2, 6, 6, 2, 6, 2, 2, 2, 2, 5, 2, 6, 6, 5, 14, 5, 6, 6, 2, 5, 2, 2, 2, 2, 6, 2, 6, 6, 2, 6, 2, 2, 2, 1, 2, 1, 2, 2, 2, 5, 2, 2, 2, 1, 2, 1, 2, 2, 2, 6, 2, 6, 6, 2, 6, 2, 2, 2, 2, 6, 2, 6, 6, 6, 14, 6, 10, 6, 6, 10, 6, 14, 10, 10, 18, 10, 18, 10, 10, 14

Offset

0,2

Links

Robert Israel, Table of n, a(n) for n = 0..10000

Maple

S:= 0: SS:= 0:
for i from 0 to 100 do
  s:= coeff(SS, x, i) mod 4;
  if s = 0 or s = 3 then
     SS:= SS + 2*expand(S*x^i)+x^(2*i); S:= S + x^i;
  fi
od:
seq(coeff(SS, x, i), i=0..100); # Robert Israel, May 14 2019

Crossrefs

Cf. A108336.

a(n) mod 4 = A083952(n).

Sequence in context: A113401 A071227 A285442 * A089254 A279861 A321431

Adjacent sequences: A108112 A108113 A108114 * A108116 A108117 A108118

Keyword

nonn

Author

N. J. A. Sloane, Jul 03 2005

Status

approved