login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A319702 Filter sequence for sequences that are constant for all even terms >= 2. 4

%I #12 Apr 07 2023 11:27:27

%S 1,2,3,2,4,2,5,2,6,2,7,2,8,2,9,2,10,2,11,2,12,2,13,2,14,2,15,2,16,2,

%T 17,2,18,2,19,2,20,2,21,2,22,2,23,2,24,2,25,2,26,2,27,2,28,2,29,2,30,

%U 2,31,2,32,2,33,2,34,2,35,2,36,2,37,2,38,2,39,2,40,2,41,2,42,2,43,2,44,2,45,2,46,2,47,2,48,2,49,2,50,2,51,2,52,2,53,2,54,2,55,2,56,2,57,2,58,2,59,2,60,2,61,2

%N Filter sequence for sequences that are constant for all even terms >= 2.

%C Restricted growth sequence transform of A141310.

%C For n > 2, a(n-1) is the number of occurrences of n in A319840. - _Stefano Spezia_, Apr 07 2023

%H Antti Karttunen, <a href="/A319702/b319702.txt">Table of n, a(n) for n = 1..100000</a>

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,2,0,-1).

%F a(1) = 1, and for n > 1, if n is even, a(n) = 2, otherwise a(n) = (n+3)/2.

%F From _Stefano Spezia_, Apr 07 2023: (Start)

%F O.g.f.: x*(1 + 2*x + x^2 - 2*x^3 - x^4)/((1 - x)^2*(1 + x)^2).

%F E.g.f.: ((4 + x)*cosh(x) + 3*sinh(x) - 2*(2 + x))/2. (End)

%o (PARI) A319702(n) = if(n<=2, n, if(!(n%2), 2, (n+3)/2));

%Y Cf. A141310, A319701, A319840.

%K nonn,easy

%O 1,2

%A _Antti Karttunen_, Oct 02 2018

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 03:51 EDT 2024. Contains 371264 sequences. (Running on oeis4.)