cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A169877 Maximum number of rational points on a smooth absolutely irreducible projective curve of genus 1 over the field F_3^n.

Original entry on oeis.org

7, 16, 38, 100, 275, 784, 2280, 6724, 19964, 59536, 177989, 532900, 1596849, 4787344, 14356482, 43059844, 129162891, 387459856, 1162329651, 3486902500, 10460557755, 31381413904, 94143792483, 282430599364, 847290450408, 2541869016976, 7625603007884, 22876802020900, 68630393933574
Offset: 1

Views

Author

N. J. A. Sloane, Jul 05 2010

Keywords

Crossrefs

Programs

  • Sage
    def a(n):
        if (n==1) or (n%2 == 0) or (floor(2*3^(n/2))%3 != 0):
            return 3^n + 1 + floor(2*3^(n/2))
        else:
            return 3^n + floor(2*3^(n/2))  # Robin Visser, Aug 17 2023

Formula

a(n) = 3^n + 1 + floor(2*3^(n/2)) if 3 does not divide floor(2*3^(n/2)), n is even, or n = 1. Otherwise a(n) = 3^n + floor(2*3^(n/2)) [Deuring-Waterhouse]. - Robin Visser, Aug 17 2023

Extensions

More terms from Robin Visser, Aug 17 2023