OFFSET
0,1
COMMENTS
This is based on Lars Blomberg's data in A333288.
A333288 is a triangular array read by rows. a(n) is the central term in row 2n+1 of that triangle, divided by 2.
See A331452 for further illustrations.
It would be nice to have a formula for this sequence. It is possible that focusing on the points (n, a(n)) where 2n+1 is a prime might lead to a simpler formula.
LINKS
Scott R. Shannon, Colored illustration for a(0): there are 4 regions, so a(0) = 2.
Scott R. Shannon, Colored illustration for a(1): the central square has 22 regions, so a(1) = 11.
Scott R. Shannon, Colored illustration for a(2): the central square has 70 regions, so a(2) = 35.
Scott R. Shannon, Colored illustration for a(3): the central square has 160 regions, so a(3) = 80.
Scott R. Shannon, Colored illustration for a(4): the central square has 310 regions, so a(4) = 155.
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 17 2020
STATUS
approved