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A161482
Nonnegative values x of solutions (x, y) to the Diophantine equation x^2+(x+151)^2 = y^2.
4
0, 96, 189, 453, 969, 1496, 3020, 6020, 9089, 17969, 35453, 53340, 105096, 207000, 311253, 612909, 1206849, 1814480, 3572660, 7034396, 10575929, 20823353, 40999829, 61641396, 121367760, 238964880, 359272749, 707383509, 1392789753
OFFSET
1,2
COMMENTS
Corresponding values y of solutions (x, y) are in A161483.
lim_{n -> infinity} a(n)/a(n-3) = 3+2*sqrt(2).
lim_{n -> infinity} a(n)/a(n-1) = (187+78*sqrt(2))/151 for n mod 3 = {1, 2}.
lim_{n -> infinity} a(n)/a(n-1) = (24723+6758*sqrt(2))/151^2 for n mod 3 = 0.
FORMULA
a(n) = 6*a(n-3)-a(n-6)+302 for n > 6; a(1)=0, a(2)=96, a(3)=189, a(4)=453, a(5)=969, a(6)=1496.
G.f.: x*(96+93*x+264*x^2-60*x^3-31*x^4-60*x^5) / ((1-x)*(1-6*x^3+x^6)).
a(3*k+1) = 151*A001652(k) for k >= 0.
MATHEMATICA
LinearRecurrence[{1, 0, 6, -6, 0, -1, 1}, {0, 96, 189, 453, 969, 1496, 3020}, 30] (* Harvey P. Dale, Jul 10 2023 *)
PROG
(PARI) {forstep(n=0, 100000000, [1, 3], if(issquare(2*n^2+302*n+22801), print1(n, ", ")))}
CROSSREFS
Cf. A161483, A001652, A156035 (decimal expansion of 3+2*sqrt(2)), A161484 (decimal expansion of (187+78*sqrt(2))/151), A161485 (decimal expansion of (24723+6758*sqrt(2))/151^2).
Sequence in context: A178740 A090762 A206337 * A352975 A044428 A044809
KEYWORD
nonn
AUTHOR
Klaus Brockhaus, Jun 13 2009
STATUS
approved