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!)
A230497 a(n), n>=2, is the minimal odd evil k, such that k^i, i=2,3,...,n, all are odious, and a(n)=0, if there is no such k. 3

%I #12 Aug 03 2023 03:45:33

%S 5,23,71,85,89,163,225,225,225,225,6075,6075,9859,9859,9859,9859,9859,

%T 9859,5031037,10430265,11896187,11896187,11896187,22402429,340713205,

%U 570919625,570919625,570919625,1496195709,1496195709,1496195709,5743845611,8271306199,8271306199,8271306199

%N a(n), n>=2, is the minimal odd evil k, such that k^i, i=2,3,...,n, all are odious, and a(n)=0, if there is no such k.

%C A conjugate sequence to A230495 and A230496.

%C Conjecture: For all n, a(n) > 0.

%t odQ[n_] := OddQ[DigitCount[n, 2, 1]]; odExp[n_] := Module[{e = 1, p = n^2}, If[! odQ[n], While[odQ[p], p *= n; e++]]; e]; seq[nmax_] := Module[{e, emax = 1, n = 3, s = {}}, Do[e = odExp[n]; If[e > emax, s = Join[s, ConstantArray[n, e - emax]]; emax = e], {n, 3, nmax, 2}]; s]; seq[10000] (* _Amiram Eldar_, Aug 03 2023 *)

%Y Cf. A000069, A001969, A230454, A230495, A230496.

%K nonn,base

%O 2,1

%A _Vladimir Shevelev_ and _Peter J. C. Moses_, Oct 21 2013

%E a(26)-a(36) from _Amiram Eldar_, Aug 03 2023

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 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)