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A023114 Numbers n such that n remains square when digit 9 is appended. 0
0, 4, 16, 324, 6400, 23716, 467856, 9229444, 34199104, 674648676, 13308852496, 49315084900, 972842923584, 19191356070436, 71112318227344, 1402838821160100, 27673922144716864, 102543913568745796, 2022892607269941264 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The terms of the sequence are the squares of the y-values in the solution to the Pellian equation x^2-10*y^2=9. - Colin Barker, Sep 28 2013

LINKS

Table of n, a(n) for n=1..19.

FORMULA

Empirical G.f.: -4*x^2*(x+1)*(x^4+2*x^3+75*x^2+2*x+1) / ((x-1)*(x^6-1442*x^3+1)). [Colin Barker, Jan 31 2013]

CROSSREFS

Sequence in context: A273474 A095956 A014731 * A207851 A202681 A067211

Adjacent sequences:  A023111 A023112 A023113 * A023115 A023116 A023117

KEYWORD

nonn,base

AUTHOR

David W. Wilson

STATUS

approved

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Last modified February 23 12:35 EST 2019. Contains 320431 sequences. (Running on oeis4.)