A090773 Numbers that are congruent to {4, 6} mod 10.

4, 6, 14, 16, 24, 26, 34, 36, 44, 46, 54, 56, 64, 66, 74, 76, 84, 86, 94, 96, 104, 106, 114, 116, 124, 126, 134, 136, 144, 146, 154, 156, 164, 166, 174, 176, 184, 186, 194, 196, 204, 206, 214, 216, 224, 226, 234, 236, 244, 246, 254, 256, 264, 266, 274, 276, 284

Offset

1,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (1,1,-1)

Formula

a(n) = 2 * A047221(n) = 5*n-5/2-3*(-1)^n/2.

a(n) = 10*n-a(n-1)-10 (with a(1)=4). - Vincenzo Librandi, Nov 16 2010

G.f.: 2*x*(2+x+2*x^2) / ( (1+x)*(x-1)^2 ). - R. J. Mathar, Oct 08 2011

Sum_{n>=1} (-1)^(n+1)/a(n) = sqrt(1-2/sqrt(5))*Pi/10. - Amiram Eldar, Dec 28 2021

Mathematica

#+{4, 6}&/@(10Range[0, 50])//Flatten (* or *) LinearRecurrence[{1, 1, -1}, {4, 6, 14}, 100] (* Harvey P. Dale, Jun 05 2017 *)

Crossrefs

Cf. A047221, A090298.

Sequence in context: A089377 A310620 A310621 * A310622 A310623 A310624

Adjacent sequences: A090770 A090771 A090772 * A090774 A090775 A090776

Keyword

nonn

Author

Giovanni Teofilatto, Feb 07 2004

Extensions

Edited and extended by Ray Chandler, Feb 10 2004

Status

approved