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A151979 Numbers == 0 or 1 mod 19. 3
0, 1, 19, 20, 38, 39, 57, 58, 76, 77, 95, 96, 114, 115, 133, 134, 152, 153, 171, 172, 190, 191, 209, 210, 228, 229, 247, 248, 266, 267, 285, 286, 304, 305, 323, 324, 342, 343, 361, 362, 380, 381, 399, 400, 418, 419, 437, 438, 456, 457, 475, 476, 494, 495, 513, 514, 532 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Numbers n such that n^2 - n is divisible by 19.

LINKS

Table of n, a(n) for n=1..57.

FORMULA

a(n+1) = Sum_k>=0 {A030308(n,k)*b(k)} with b(0)=1 and b(k)=19*2^(k-1) for k>0. - From Philippe Deléham, Oct 19 2011.

a(n) = a(n-1)+a(n-2)-a(n-3). G.f.: x^2*(1+18*x)/((1-x)^2*(1+x)). - Colin Barker, Apr 09 2012

PROG

(MAGMA) [ n : n in [0..600] | n mod 19 eq 0 or n mod 19 eq 1] [From Vincenzo Librandi, Jan 26 2011]

CROSSREFS

Sequence in context: A007640 A241849 A054304 * A022109 A041730 A041732

Adjacent sequences:  A151976 A151977 A151978 * A151980 A151981 A151982

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Aug 23 2009

STATUS

approved

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Last modified November 26 10:08 EST 2014. Contains 250038 sequences.