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 A074458 #27 Mar 09 2024 11:06:43
%S A074458 6,2,5,5,4,5,6,4,7,5,8,4,7,7,6,7,8,6,9,7,11,7,10,10,9,10,11,9,12,10,
%T A074458 11,7,10,10,9,10,11,9,12,10,10,6,9,9,8,9,10,8,11,9,11,7,10,10,9,10,11,
%U A074458 9,12,10,12,8,11,11,10,11,12,10,13,11,10,6,9,9,8,9,10,8,11
%N A074458 Number of segments lit to display the number n on a 7-segment display (as in pocket calculators): variant where '6', '7' and '9' use 6, 4 resp. 5 segments.
%C A074458 Sequences A234691 and A234692 use one bit for each lit segment. See crossrefs for other variants. - _M. F. Hasler_, Jun 17 2020
%H A074458 <a href="/index/Ca#calculatordisplay">Index entries for sequences related to calculator display</a>
%F A074458 From _M. F. Hasler_, Jun 17 2020: (Start)
%F A074458 a(n) = a(n mod 10) + a(floor(n/10)) for n > 9.
%F A074458 a(n) = A006942(n) - A102679(n) + A102681(n). (End)
%e A074458 LED display:
%e A074458 _ _ _ _ _ _ _ _
%e A074458 | | | _| _| |_| |_ |_ | | |_| |_|
%e A074458 |_| | |_ _| | _| |_| | |_| |
%e A074458 .
%e A074458 so we have a(0) = 6, a(1) = 2, a(2) = 5 ...
%o A074458 (PARI) apply( {A074458(n)=digits(6255456475)[n%10+1]+if(n>9,self()(n\10))}, [0..99]) \\ _M. F. Hasler_, Jun 17 2020
%Y A074458 Cf. A074459.
%Y A074458 For other versions of this sequence, see A006942 (7 with one segment less), A063720 (6 and 7 with one segment less), A010371 (9 with one segment more), A277116 (7 with one segment less, 9 with one segment more).
%Y A074458 Cf. A234691, A234692, A000120.
%K A074458 nonn,base
%O A074458 0,1
%A A074458 Y. Kelly Itakura (yitkr(AT)mta.ca), Aug 22 2002
%E A074458 Example edited by _Jon E. Schoenfield_, Jul 30 2017
%E A074458 Edited and extended to n > 9 by _M. F. Hasler_, Jun 17 2020