This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A140659 a(n) = floor(A140657(n+2)/10). 1
 0, 0, 1, 2, 6, 12, 25, 50, 102, 204, 409, 818, 1638, 3276, 6553, 13106, 26214, 52428, 104857, 209714, 419430, 838860, 1677721, 3355442, 6710886, 13421772, 26843545, 53687090, 107374182, 214748364, 429496729, 858993458, 1717986918, 3435973836 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS Michel Marcus, Table of n, a(n) for n = 0..100 FORMULA a(2n+2) = 4*a(2n)+A000034(n). a(2n+1) = 2*a(2n). MATHEMATICA a[ n_] := If[n < 2, 0, 2 a[n - 1] + If[ EvenQ[n], Mod[n/2, 2, 1], 0]]; (* Michael Somos, Mar 02 2014 *) PROG (PARI) f(n) = 2^n+3*(-1)^n; \\ A140657 a(n) = f(n+2)\10; \\ Michel Marcus, Sep 08 2019 CROSSREFS Cf. A093387. Sequence in context: A116562 A045925 A128020 * A238462 A099495 A232164 Adjacent sequences:  A140656 A140657 A140658 * A140660 A140661 A140662 KEYWORD nonn AUTHOR Paul Curtz, Jul 10 2008 EXTENSIONS Edited and extended by R. J. Mathar, Jul 29 2008 Name corrected by Michel Marcus, Sep 08 2019 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 15 20:00 EST 2019. Contains 330000 sequences. (Running on oeis4.)