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Powers of 2 with initial digit 9.
1

%I #12 Nov 21 2018 12:23:55

%S 9007199254740992,9223372036854775808,9444732965739290427392,

%T 9671406556917033397649408,9903520314283042199192993792,

%U 91343852333181432387730302044767688728495783936,93536104789177786765035829293842113257979682750464

%N Powers of 2 with initial digit 9.

%H Muniru A Asiru, <a href="/A320865/b320865.txt">Table of n, a(n) for n = 1..150</a>

%H <a href="/index/Di#divseq">Index to divisibility sequences</a>

%p select(x->"9"=""||x[1],[2^n$n=0..200])[];

%t Select[2^Range[200], IntegerDigits[#][[1]] == 9 &] (* _Amiram Eldar_, Nov 21 2018 *)

%o (GAP) Filtered(List([0..200],n->2^n),i->ListOfDigits(i)[1]=9);

%o (PARI) select(x->(digits(x)[1]==9), vector(200, n, 2^n)) \\ _Michel Marcus_, Nov 21 2018

%Y Cf. A000079 (powers of 2), A008952 (leading digit of 2^n), A217402 (numbers starting with 9).

%Y Powers of 2 with initial digit k, (k = 1..9): A067488, A067480, A320859, A320860, A320861, A320862, A320863, A320864, this sequence.

%K base,nonn

%O 1,1

%A _Muniru A Asiru_, Nov 21 2018