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A157622 31250n - 9100. 3
22150, 53400, 84650, 115900, 147150, 178400, 209650, 240900, 272150, 303400, 334650, 365900, 397150, 428400, 459650, 490900, 522150, 553400, 584650, 615900, 647150, 678400, 709650, 740900, 772150, 803400, 834650, 865900, 897150, 928400 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
The identity (781250*n^2-455000*n+66249)^2-(625*n^2-364*n+53)*(31250*n-9100)^2=1 can be written as A157623(n)^2-A157621(n)*a(n)^2=1.
LINKS
Vincenzo Librandi, X^2-AY^2=1
FORMULA
a(n) = 2*a(n-1) - a(n-2).
G.f.: x*(22150+9100*x)/(x-1)^2.
MATHEMATICA
LinearRecurrence[{2, -1}, {22150, 53400}, 30]
31250*Range[30]-9100 (* Harvey P. Dale, Nov 16 2018 *)
PROG
(Magma) I:=[22150, 53400]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..40]];
(PARI) a(n) = 31250*n-9100.
CROSSREFS
Sequence in context: A062564 A043590 A043815 * A225392 A225998 A209396
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Mar 03 2009
STATUS
approved

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Last modified June 22 12:42 EDT 2024. Contains 373571 sequences. (Running on oeis4.)