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%I #12 Oct 22 2018 17:02:33
%S 1,16,1024,16384,1048576,16777216,1073741824,17179869184,
%T 1099511627776,17592186044416,1125899906842624,18014398509481984,
%U 1152921504606846976,18446744073709551616,1180591620717411303424,18889465931478580854784,1208925819614629174706176
%N Powers of 4 with initial digit 1.
%H Muniru A Asiru, <a href="/A067490/b067490.txt">Table of n, a(n) for n = 1..400</a>
%H <a href="/index/Di#divseq">Index to divisibility sequences</a>
%F a(n+1)/a(n) is in {16, 64, 1024}, so 16^n <= a(n+1) < 1024^n. Asymptotically, the exponent should be 100; I can prove that 99^n << a(n) << 101^n. [_Charles R Greathouse IV_, Jan 19 2012]
%p select(x-> "1"=""||x[1],[4^n$n=0..60])[]; # _Alois P. Heinz_, Oct 22 2018
%o (GAP) Filtered(List([0..40],n->4^n),i->ListOfDigits(i)[1]=1); # _Muniru A Asiru_, Oct 22 2018
%Y Cf. A067480, A067481, A067482, A067483, A067484, A067485, A067486, A067487, A067488, A067489.
%K base,easy,nonn
%O 1,2
%A _Amarnath Murthy_, Feb 09 2002
%E a(16) inserted by _Muniru A Asiru_, Oct 22 2018
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