A267185 Column 2 of the square array in A267181.

0, 1, 0, 4, 2, 5, 3, 6, 4, 7, 5, 8, 6, 9, 7, 10, 8, 11, 9, 12, 10, 13, 11, 14, 12, 15, 13, 16, 14, 17, 15, 18, 16, 19, 17, 20, 18, 21, 19, 22, 20, 23, 21, 24, 22, 25, 23, 26, 24, 27, 25, 28, 26, 29, 27, 30, 28, 31, 29, 32, 30, 33, 31, 34, 32, 35, 33, 36, 34, 37, 35

Offset

0,4

Links

Table of n, a(n) for n=0..70.

Formula

Conjectures from Colin Barker, Jan 29 2016: (Start)

a(n) = (2*n-5*((-1)^n-1))/4 for n>2.

a(n) = n/2 for n>2 and even.

a(n) = (n+5)/2 for n>2 and odd.

a(n) = a(n-1)+a(n-2)-a(n-3) for n>5.

G.f.: x*(1-x+3*x^2-x^3-x^4) / ((1-x)^2*(1+x)).

(End)

Crossrefs

Cf. A267181.

Sequence in context: A123152 A309567 A243855 * A065187 A185511 A199855

Adjacent sequences: A267182 A267183 A267184 * A267186 A267187 A267188

Keyword

nonn

Author

N. J. A. Sloane, Jan 17 2016

Status

approved