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A334525

Number of ordered triples (w,x,y) with all terms in {-n,...,0,...,n} and w^2 + 7xy = 0.

1, 5, 9, 13, 17, 21, 25, 37, 41, 45, 49, 53, 57, 61, 81, 85, 89, 93, 97, 101, 105, 125, 129, 133, 137, 141, 145, 149, 185, 189, 193, 197, 201, 205, 209, 229, 233, 237, 241, 245, 249, 253, 297, 301, 305, 309, 313, 317, 321, 333, 337, 341, 345, 349, 353, 357, 393, 397

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

COMMENTS

If n is squarefree and not divisible by 7, a(n) = a(n-1)+4. - Robert Israel, Jul 01 2020

LINKS

Brandon Crofts, Table of n, a(n) for n = 0..20000

Brandon Crofts, Mathematica code for A334525

MAPLE

df:= proc(n) local t, s, m0, m;

if n mod 7 = 0 then

m:= n/7;