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A097579 Numbers n such that n and 2*n-1 are triangular numbers. 0
1, 28, 946, 32131, 1091503, 37078966, 1259593336, 42789094453, 1453569618061, 49378577919616, 1677418079648878, 56982836130142231, 1935739010345186971, 65758143515606214778, 2233841140520266115476, 75884840634173441711401 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..16.

FORMULA

G.f.: x*(1-7*x+x^2)/((1-x)*(1-34*x+x^2)).

MATHEMATICA

CoefficientList[ Series[x*(1 - 7*x + x^2)/((1 - x)*(1 - 34*x + x^2)), {x, 0, 16}], x] (* Robert G. Wilson v, Sep 01 2004 *)

CROSSREFS

Cf. A075528, A124174.

Sequence in context: A129461 A239336 A203135 * A091549 A034904 A189995

Adjacent sequences:  A097576 A097577 A097578 * A097580 A097581 A097582

KEYWORD

easy,nonn

AUTHOR

Vladeta Jovovic, Aug 29 2004

EXTENSIONS

More terms from Robert G. Wilson v, Sep 01 2004

STATUS

approved

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Last modified December 15 03:52 EST 2018. Contains 318141 sequences. (Running on oeis4.)