A067869 - OEIS

%I #20 Jun 17 2017 03:04:36

%S 48736,148736,248736,348736,448736,548736,648736,748736,848736,948736,

%T 1048736,1148736,1248736,1348736,1448736,1548736,1648736,1748736,

%U 1848736,1948736,2048736,2148736,2248736,2348736,2448736,2548736

%N Numbers n such that n and 2^n end with the same 5 digits.

%H Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).

%F a(n) = 48736+10^5(n-1).

%F a(n) = 2*a(n-1)-a(n-2). G.f.: x*(48736+51264*x)/(1-x)^2. - _Colin Barker_, Jun 05 2012

%o (PARI) isok(n) = (2^n - n) % 100000 == 0; \\ _Michel Marcus_, Nov 23 2013

%Y Cf. A064541.

%Y Subsequence of A067844, A067845, A067846, and A067847.

%K nonn,base,easy

%O 1,1

%A _Benoit Cloitre_, Mar 07 2002