A331448 a(0) = 0 by convention; for n>0, a(n) is the number of edges in the n-th figure shown in A255011 (meaning the figure with 4n points on the perimeter).

0, 8, 92, 596, 1936, 6020, 11088, 26260, 42144, 72296, 107832, 183340, 222940, 371100, 466936, 609916, 804504, 1139632, 1288536, 1813288, 2012676, 2536572, 3142008, 3997580, 4230340, 5430444, 6331892, 7360512, 8262568, 10367804

Offset: 0

Author

N. J. A. Sloane, Jan 23 2020, based on a comment from Michael De Vlieger in A255011

Keywords

• nonn

Comments

By Euler's formula, a(n) = A331449(n) + A255011(n) - 1.

Links

• Zhao Hui Du, Table of n, a(n) for n = 0..136 (terms 0..52 from Lars Blomberg).

Crossrefs

Cf. A255011, A331449.

For the circular analog see A006533, A007678, A007569, A135565.

Extensions

a(11)-a(29) from Giovanni Resta, Jan 28 2020