A256571 a(n) is the total number of pentagrams in a variant of pentagram fractal after n iterations.

1, 6, 21, 56, 131, 281, 556, 1046, 1896, 3346, 5796, 9916, 16806, 28316, 47506, 79476, 132706

Offset

1,2

Comments

Inspired by A255870. But at the higher iterations, the perimeter is an irregular polygon instead of a pentagon. The construction rule is sides to vertices expansion. See illustration in the links.

Links

Table of n, a(n) for n = 1..17

Kival Ngaokrajang, Illustration of initial terms

Crossrefs

Cf. A255870, A256429, A256569.

Sequence in context: A346893 A337895 A145134 * A247904 A074745 A296821

Adjacent sequences: A256568 A256569 A256570 * A256572 A256573 A256574

Keyword

nonn,more

Author

Kival Ngaokrajang, Apr 02 2015

Extensions

a(9) corrected and a(10)-a(15) added by Udo Vieth, Jan 16 2023

a(16)-a(17) added by Udo Vieth, Aug 19 2024

Status

approved