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%I #7 Jan 02 2023 12:30:50
%S 12,18,21,24,27,36,42,45,48,54,63,72,81,84,102,105,108,110,126,132,
%T 144,147,162,168,189,198,201,204,207,209,216,220,231,243,264,288,297,
%U 306,308,324,330,396,402,405,407,408,414,418,429,432,440,462,486,495,504,506,510,528,540,550,567,594,603,605,612,616,621,627,648
%N Knife numbers (second version): n=concat(a,b) is divisible by a+b; a>0; b must not have leading zeros.
%C Here, b must not have leading zeros but may be zero, in contrast to the subsequence A247624 and the alternate variant A247627. Sequence A247626 is less restrictive, allowing leading zeros in b.
%H E. Angelini, <a href="http://list.seqfan.eu/oldermail/seqfan/2014-September/013661.html">Knife numbers</a>.
%o (PARI) is(n,u=[1,1])=n&&for(k=1,#Str(n)-1,n%(u*divrem(n,10^k))==0&&(n%10^k)&&return(1))
%K nonn,base
%O 1,1
%A _M. F. Hasler_ and _Eric Angelini_, Sep 21 2014
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