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 A133192 #4 Mar 30 2012 18:40:43 %S A133192 8,13,14,16,19,21,41,53,54,56,59,61,91,103,104,106,109,111,151,201, %T A133192 400,502,505,510,550,600,1001,5002,5005,5010,5050,5100,10002,10005, %U A133192 10010,10050,10100,50002,50005,50010,50050,50100,100002,100005,100010,100050,100100,500001,1000000 %N A133192 Numbers that require exactly five chisel strokes when written in Roman numerals. %F A133192 Numbers n such that A002963(n) = 5. %e A133192 Chisel strokes for numerals: I,1; V,2; X,2; L,2; C ( = < ),2; D,3; M,4; 5000 is V with a line over it, 3; 10000 is X with a line over it, 3; 50000 is L with a line over it, 3; 100000 is L with a line over it, 3; 500000 is D with a line over it, 4; 1000000 is M with a line over it, 5. Numerals with two horizontal strokes over them were not common in historical Rome. A002964 has a different evaluation of the strokes of C, as does A118098. %Y A133192 Cf. A002963, A002964, A118098. %K A133192 base,fini,full,nonn %O A133192 1,1 %A A133192 _Jonathan Vos Post_, Oct 09 2007