A269298 Central nonzero values of A231599.

1, 2, 2, 4, 6, 8, 16, 28, 50, 100, 196, 388, 786, 1600, 3280, 6780, 14060, 29280, 61232, 128414, 270084, 569514, 1203564, 2548770, 5407754, 11493312, 24465960, 52157508, 111342192, 237985596, 509275390, 1091017632, 2339687834, 5022312654, 10790564790

Offset: 0

Author

Tilman Piesk, Feb 21 2016

Keywords

• nonn

Comments

Rows of A231599 whose row number is divisible by four have positive central values. a(n) is the central value of row 4n. They are also the maximal value of that row, so a(n) = A086376(4n).

a(1) = a(2) = 2. Apart from that the sequence is strictly increasing.

Examples

			For n = 5, A231599( 4n, A000217(4n)/2 ) = A231599(20, 105) = 8, so a(5)=8.
For n = 5, A086376(4n) = A086376(20) = 8, so a(5)=8.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..250 (first 101 trms from Tilman Piesk)
• Dorin Andrica and Ovidiu Bagdasar, On some results concerning the polygonal polynomials, Carpathian Journal of Mathematics (2019) Vol. 35, No. 1, 1-11.
• Tilman Piesk, A231599 as a centered table (first 11 values visible)

Crossrefs

Cf. A231599, A086376.

Formula

a(n) = A231599( 4n, A000217(4n)/2 ) = A086376(4n).