This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A123384 #28 Aug 31 2024 11:08:12
%S A123384 1,4,7,10,14,17,20,24,27,30,34,37,40,44,47,50,54,57,60,64,67,70,74,77,
%T A123384 80,84,87,90,94,97,100,103,107,110,113,117,120,123,127,130,133,137,
%U A123384 140,143,147,150,153,157,160,163,167,170,173,177,180,183,187,190,193,196
%N A123384 Number of bits in binary expansion of 10^n.
%C A123384 Number of powers of 2 less than or equal to 10^n. - _Peter Munn_, Nov 13 2019
%F A123384 a(n) = 1 + floor(n/A007524) = 1 + floor(n/log_10(2)). - _R. J. Mathar_, Nov 12 2006
%F A123384 a(n) = 1 + A066343(n). - _R. J. Mathar_, Mar 02 2007
%F A123384 a(n) = A067497(n) for n >= 1. - _Georg Fischer_, Nov 02 2018
%e A123384 a(3)=10 because 10^3 = 1111101000_2.
%e A123384 10^1 = 10 = 1010_2 has 4 digits.
%p A123384 A007524 := log[10](2.0) ; for n from 0 to 40 do printf("%d,", 1+floor(n/A007524)) ; od: # _R. J. Mathar_, Nov 12 2006
%p A123384 a:=n->nops(convert(10^n,base,2)): seq(a(n),n=0..70); # _Emeric Deutsch_, Mar 26 2007
%t A123384 a[n_]:=1 + Floor[n/Log10[2]]; Array[a,60,0] (* _Stefano Spezia_, Aug 31 2024 *)
%Y A123384 Cf. A000079, A007524, A011557, A066343, A067497.
%Y A123384 Row 1 of A253635.
%K A123384 base,nonn
%O A123384 0,2
%A A123384 Andrew Caldwell (spongebobpj(AT)yahoo.com), Nov 09 2006
%E A123384 More terms from _Emeric Deutsch_, Mar 26 2007