The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A245179 Numbers of the form 2^k+3 or 3*2^k+1, k >= 2. 2
 7, 11, 13, 19, 25, 35, 49, 67, 97, 131, 193, 259, 385, 515, 769, 1027, 1537, 2051, 3073, 4099, 6145, 8195, 12289, 16387, 24577, 32771, 49153, 65539, 98305, 131075, 196609, 262147, 393217, 524291, 786433, 1048579, 1572865, 2097155, 3145729, 4194307, 6291457 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numbers whose binary expansion is 10..011 or 110..01. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (0,3,0,-2). FORMULA a(2k) = 2^(k+2)+3, a(2k+1) = 3*2^(k+1)+1. - N. J. A. Sloane, Jul 19 2014 a(n) = 3*a(n-2)-2*a(n-4). G.f.: -x*(14*x^3+8*x^2-11*x-7) / ((x-1)*(x+1)*(2*x^2-1)). - Colin Barker, Jul 19 2014 MATHEMATICA CoefficientList[Series[- (14 x^3 + 8 x^2 - 11 x - 7)/((x - 1) (x + 1) (2 x^2 - 1)), {x, 0, 50}], x] (* Vincenzo Librandi, Jul 23 2014 *) LinearRecurrence[{0, 3, 0, -2}, {7, 11, 13, 19}, 50] (* Harvey P. Dale, Mar 05 2015 *) PROG (MAGMA) &cat [[3*2^i+1, 2^(i+2)+3]: i in [1..30]]; // Bruno Berselli, Jul 23 2014 CROSSREFS Essentially the union of A062709 and A181565. Cf. A245178. Sequence in context: A155488 A100350 A084467 * A297177 A239710 A227921 Adjacent sequences:  A245176 A245177 A245178 * A245180 A245181 A245182 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Jul 17 2014 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 7 22:50 EST 2021. Contains 349590 sequences. (Running on oeis4.)