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A106330 Numbers k such that k^2 = 24*(j^2) + 25. 1
5, 7, 11, 25, 59, 103, 245, 583, 1019, 2425, 5771, 10087, 24005, 57127, 99851, 237625, 565499, 988423, 2352245, 5597863, 9784379, 23284825, 55413131, 96855367, 230496005, 548533447, 958769291, 2281675225, 5429921339, 9490837543, 22586256245, 53750679943 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The ratio k(n) /(2*j(n)) tends to sqrt(6) as n increases.

LINKS

Table of n, a(n) for n=1..32.

Index entries for linear recurrences with constant coefficients, signature (0,0,10,0,0,-1).

FORMULA

Recurrence: k(1)=5, k(2)=7, k(3)=11, k(4)=25, k(5)=10*k(2)-k(3), k(6)=10*k(3)-k(2) then k(n)=10*k(n-3)-k(n-6).

G.f.: (-7x^5-11x^4-25x^3+11x^2+7x+5)/(x^6-10x^3+1).

a(3n+1) = 5*A001079(n), a(3n+2) = A077409(n), a(3n+3) = A077250(n).

PROG

(PARI) Vec(-x*(7*x^5+11*x^4+25*x^3-11*x^2-7*x-5)/(x^6-10*x^3+1) + O(x^100)) \\ Colin Barker, Apr 16 2014

CROSSREFS

Cf. A106331.

Sequence in context: A067289 A036491 A036490 * A057247 A157437 A213677

Adjacent sequences:  A106327 A106328 A106329 * A106331 A106332 A106333

KEYWORD

nonn,easy

AUTHOR

Pierre CAMI, Apr 29 2005

EXTENSIONS

More terms, g.f. and formulas from Ralf Stephan, Nov 15 2010

More terms from Colin Barker, Apr 16 2014

STATUS

approved

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Last modified November 25 20:42 EST 2020. Contains 338627 sequences. (Running on oeis4.)