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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
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
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 March 19 07:04 EDT 2024. Contains 370953 sequences. (Running on oeis4.)