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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A251549 a(n) = smallest odd number not in {A098550(1), A098550(2), ..., A098550(n)}. 6

%I

%S 3,3,5,5,5,5,5,5,7,7,7,7,7,7,11,11,11,11,11,11,11,13,17,17,17,17,17,

%T 17,17,19,19,19,19,19,19,19,19,19,19,19,19,19,23,23,23,23,23,23,23,23,

%U 29,29,29,29,29,29,29,29,29

%N a(n) = smallest odd number not in {A098550(1), A098550(2), ..., A098550(n)}.

%C A251416(n) = Min{A251546(n), a(n)}. - _Reinhard Zumkeller_, Dec 19 2014

%H Chai Wah Wu, <a href="/A251549/b251549.txt">Table of n, a(n) for n = 1..10000</a>

%t terms = 100;

%t f[lst_List] := Block[{k=4}, While[GCD[lst[[-2]], k] == 1 || GCD[lst[[-1]], k] > 1 || MemberQ[lst, k], k++]; Append[lst, k]];

%t A098550 = Nest[f, {1, 2, 3}, terms-3];

%t a[1] = 3;

%t a[n_] := a[n] = For[k = a[n-1], True, k = k+2, If[FreeQ[A098550[[1 ;; n]], k], Return[k]]];

%t Array[a, terms] (* _Jean-Fran├žois Alcover_, Aug 02 2018, after _Robert G. Wilson v_ *)

%o (Haskell)

%o import Data.List ((\\))

%o a251549 n = head $ [1, 3 ..] \\ filter odd (take n a098550_list)

%o -- _Reinhard Zumkeller_, Dec 19 2014

%Y Cf. A098550, A247253, A251416, A251417, A251546-A251552.

%K nonn

%O 1,1

%A _N. J. A. Sloane_, Dec 18 2014

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 4 23:59 EDT 2020. Contains 333238 sequences. (Running on oeis4.)