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A161617 8*n^2+20*n+1. 6
1, 29, 73, 133, 209, 301, 409, 533, 673, 829, 1001, 1189, 1393, 1613, 1849, 2101, 2369, 2653, 2953, 3269, 3601, 3949, 4313, 4693, 5089, 5501, 5929, 6373, 6833, 7309, 7801, 8309, 8833, 9373, 9929, 10501, 11089, 11693, 12313, 12949, 13601 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The defining formula can be regarded as an approximation and simplification of the expansion / propagation of native hydrophytes on the surface of stagnant waters in orthogonal directions; absence of competition / concurrence and of retrogression is assumed, mortality is taken into account. - (Translation of a comment in French sent by P. Gayet)

LINKS

Pierre Gayet, Table of n, a(n) for n = 0..9999

Pierre Gayet, Note et Compte rendu (gif version)

Pierre Gayet, Note et Compte Rendu (pdf version)

Pierre Gayet, 98 séquences générées ... par la formule générale indiquée

Claude Monet, Nymphéas

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

FORMULA

a(n) = a(n-1)+16*n+12 (with a(0)=1). - Vincenzo Librandi, Nov 30 2010

PROG

(MAGMA) [ 8*n^2+20*n+1: n in [0..50] ];

(PARI) a(n)=8*n^2+20*n+1 \\ Charles R Greathouse IV, Jun 17 2017

CROSSREFS

Cf. A161532, A161549, A161587, A161935, A162316.

Sequence in context: A139893 A063312 A210499 * A142305 A184072 A071110

Adjacent sequences:  A161614 A161615 A161616 * A161618 A161619 A161620

KEYWORD

easy,nonn

AUTHOR

Pierre Gayet, Jun 14 2009

STATUS

approved

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Last modified September 26 11:22 EDT 2021. Contains 347665 sequences. (Running on oeis4.)