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Powers of 6 with initial digit 6.
12

%I #29 Oct 20 2018 06:05:34

%S 6,60466176,609359740010496,6140942214464815497216,

%T 61886548790943213277031694336,623673825204293256669089197883129856,

%U 6285195213566005335561053533150026217291776,63340286662973277706162286946811886609896461828096

%N Powers of 6 with initial digit 6.

%C The geometric progression formula a(n)=10077696*a(n-1) does NOT hold if n=20, 40, 59, 79, 98, etc. - _R. J. Mathar_, Jun 24 2009

%H Muniru A Asiru, <a href="/A067484/b067484.txt">Table of n, a(n) for n = 1..89</a>

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

%p A067484 := proc(n) local p6,p,a ; if n = 1 then 6; else p6 := procname(n-1) ; ifactors(p6)[2] ; p := op(2,op(1,%)) ; for a from p+1 do p6 := 6^a ; convert(%,base,10) ; if op(-1,%) = 6 then RETURN(p6) ; fi; od: fi; end: # _R. J. Mathar_, Jun 24 2009

%t Select[6^Range[100],First[IntegerDigits[#]]==6&] (* _Harvey P. Dale_, Aug 14 2018 *)

%o (GAP) k:=6;; Filtered(List([0..80],n->k^n),i->ListOfDigits(i)[1]=k); # _Muniru A Asiru_, Oct 18 2018

%Y Cf. A067480, A067481, A067482, A067483.

%K base,easy,nonn

%O 1,1

%A _Amarnath Murthy_, Feb 09 2002

%E More terms from _Benoit Cloitre_, Feb 22 2002

%E a(8) from _Harvey P. Dale_, Aug 14 2018

%E Offset changed to 1 by _Muniru A Asiru_, Oct 19 2018