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 A103127 Numbers congruent to {-1, 1, 3, 5} mod 16. 4
 1, 3, 5, 15, 17, 19, 21, 31, 33, 35, 37, 47, 49, 51, 53, 63, 65, 67, 69, 79, 81, 83, 85, 95, 97, 99, 101, 111, 113, 115, 117, 127, 129, 131, 133, 143, 145, 147, 149, 159, 161, 163, 165, 175, 177, 179, 181, 191, 193, 195, 197, 207, 209, 211, 213, 223, 225, 227, 229, 239, 241 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Agrees with A103192 for the first 511 terms, but then diverges (see comment in A103192). - Bruno Berselli, Dec 01 2016 Conjecture: satisfies a linear recurrence having signature (1, 0, 0, 1, -1). - Harvey P. Dale, Aug 10 2019 LINKS David Applegate, Benoit Cloitre, Philippe Deléham and N. J. A. Sloane, Sloping binary numbers: a new sequence related to the binary numbers, J. Integer Seq. 8 (2005), no. 3, Article 05.3.6, 15 pp [pdf, ps]. FORMULA a(n) = 2*A047527(n) + 1. From R. J. Mathar, Aug 30 2008: (Start) O.g.f.: x*(1 + 2*x + 2*x^2 + 10*x^3 + x^4)/((1 - x)^2*(1 + x)*(1 + x^2)). a(n) = a(n-4) + 16. (End) a(n) = (1+i)*i^n - (-1)^n + 4*n + (1-i)*(-i)^n, with n>=0 and i=sqrt(-1). - Paolo P. Lava, Nov 19 2008 a(n) = 2*A047476(n+1) - 1. - Philippe Deléham, Dec 01 2016 MATHEMATICA Select[Range[300], MemberQ[{1, 3, 5, 15}, Mod[#, 16]]&] (* Harvey P. Dale, Aug 10 2019 *) PROG (Haskell) a103127 n = a103127_list !! (n-1) a103127_list = [x | x <- [1..], x `mod` 16 `elem` [1, 3, 5, 15]] -- Reinhard Zumkeller, Jul 21 2012 CROSSREFS Cf. A047527, A103192. Sequence in context: A066420 A102582 A089168 * A103192 A097856 A071593 Adjacent sequences:  A103124 A103125 A103126 * A103128 A103129 A103130 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Mar 25 2005 STATUS approved

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Last modified October 20 07:33 EDT 2019. Contains 328252 sequences. (Running on oeis4.)