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A113541 Numbers n such that 18n^2+1 is multiple of 19. 3
1, 18, 20, 37, 39, 56, 58, 75, 77, 94, 96, 113, 115, 132, 134, 151, 153, 170, 172, 189, 191, 208, 210, 227, 229, 246, 248, 265, 267, 284, 286, 303, 305, 322, 324, 341, 343, 360, 362, 379, 381, 398, 400, 417, 419, 436, 438, 455, 457, 474, 476, 493, 495, 512 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

FORMULA

a(1)=1, a(2)=18 then add alternatively 2 and 17.

a(n) = 19*(n-1) - a(n-1), (with a(1)=1). - Vincenzo Librandi, Nov 13 2010

MATHEMATICA

s={}; Do[If[IntegerQ[(18n^2+1)/19], AppendTo[s, n]], {n, 200}]; s

CROSSREFS

Sequence in context: A164711 A036170 A064271 * A181453 A113542 A075865

Adjacent sequences:  A113538 A113539 A113540 * A113542 A113543 A113544

KEYWORD

nonn

AUTHOR

Zak Seidov, Jan 13 2006

EXTENSIONS

More terms (a(22)-a(56) from Vincenzo Librandi, Oct 23 2009

STATUS

approved

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Last modified January 29 16:58 EST 2020. Contains 331347 sequences. (Running on oeis4.)