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 A080464 #18 Aug 07 2019 12:57:42
%S A080464 0,1,2,3,4,5,6,7,8,9,0,2,4,6,8,10,12,14,16,18,0,3,6,9,12,15,18,21,24,
%T A080464 27,0,4,8,12,16,20,24,28,32,36,0,5,10,15,20,25,30,35,40,45,0,6,12,18,
%U A080464 24,30,36,42,48,54,0,7,14,21,28,35,42,49,56,63,0,8,16,24,32,40,48,56,64,72,0
%N A080464 Product of the two numbers formed by alternate digits of n.
%H A080464 M. F. Hasler, <a href="/A080464/b080464.txt">Table of n, a(n) for n = 10..10000</a>
%F A080464 a(n) < n for all n. - _M. F. Hasler_, Jan 10 2016
%e A080464 a(132546) = 124 * 356 = 44144.
%t A080464 nad[n_]:=Module[{idn=IntegerDigits[n]},FromDigits[Take[idn,{1,-1,2}]] FromDigits[ Take[idn,{2,-1,2}]]]; Array[nad,120,10] (* _Harvey P. Dale_, Aug 07 2019 *)
%o A080464 (PARI) A080464(n,d=digits(n))={n=d*matrix(#d,2,z,s,if((z-s)%2,10^((#d-z)\2)));n[1]*n[2]}
%Y A080464 Cf. A007954, A080463, A080465, A087471, A087472, A087473, A087474.
%K A080464 base,easy,nonn,look
%O A080464 10,3
%A A080464 _Amarnath Murthy_, Mar 02 2003
%E A080464 More terms from _Ray Chandler_, Oct 11 2003