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 A004770 Numbers of form 8n+5; or, numbers whose binary expansion ends in 101. 17
 5, 13, 21, 29, 37, 45, 53, 61, 69, 77, 85, 93, 101, 109, 117, 125, 133, 141, 149, 157, 165, 173, 181, 189, 197, 205, 213, 221, 229, 237, 245, 253, 261, 269, 277, 285, 293, 301, 309, 317, 325, 333, 341, 349, 357, 365, 373, 381, 389, 397, 405, 413, 421, 429 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Only numbers of the form 8n+5 may be written as a sum of 5 odd squares. Examples: 5 = 1+1+1+1+1, 13 = 9+1+1+1+1, 21 = 9+9+1+1+1, 29 = 25+1+1+1+1= 9+9+9+1+1, 37 = 9+9+9+9+1 = 25+9+1+1+1, 45 = 25+9+9+1+1=9+9+9+9+9, 53 = 49+1+1+1+1 = 25+25+1+1+1 = 25+9+9+9+1, ... - Philippe Deléham, Sep 03 2005 Positive solutions to the equation x == 5 (mod 8). - K.V.Iyer, Apr 27 2009 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..5000 Tanya Khovanova, Recursive Sequences Index entries for linear recurrences with constant coefficients, signature (2,-1) FORMULA a(n) = 8*n-3; G.f. x*(5+3*x)/(x-1)^2. - R. J. Mathar, Mar 14 2011 a(n) = 2*a(n-1) - a(n-2). - Vincenzo Librandi, May 28 2011 MATHEMATICA Range[5, 1000, 8] (* Vladimir Joseph Stephan Orlovsky, May 27 2011 *) PROG (MAGMA) [8*n-3: n in [1..60]]; // Vincenzo Librandi, May 28 2011 (Haskell) a004770 = (subtract 3) . (* 8) a004770_list = [5, 13 ..]  -- Reinhard Zumkeller, Aug 17 2012 (PARI) a(n)=8*n-3 \\ Charles R Greathouse IV, Sep 24 2015 CROSSREFS Cf. A110534, A017101, A017113. Cf. A004776 (complement), A007521 (primes). Sequence in context: A007675 A043441 A251537 * A191155 A107996 A107997 Adjacent sequences:  A004767 A004768 A004769 * A004771 A004772 A004773 KEYWORD nonn,easy AUTHOR STATUS approved

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