cp's OEIS Frontend

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.

A195144 Reversal of n equals the sum of the reversals of the anti-divisors of n.

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%I A195144 #19 Mar 30 2012 18:53:49
%S A195144 5,8,895799
%N A195144 Reversal of n equals the sum of the reversals of the anti-divisors of n.
%C A195144 Like A069942 but using anti-divisors. No other terms up to 3*10^10.
%e A195144 The first two terms are banal cases: anti-divisors of 5 are 2 and 3 and their reversals are again 5, 2 and 3 and 2+3 = 5. The same for 8: 3+5 = 8. Anti-divisors of 895799 are 2, 3, 199, 597, 3001, 9003, 597199 and 2+3+991+795+1003+3009+991795 = 997598.
%p A195144 Rev:=proc(n)
%p A195144 local a,i,k;
%p A195144   i:=convert(n,base,10); a:=0;
%p A195144   for k from 1 to nops(i) do a:=a*10+i[k]; od;
%p A195144   a;
%p A195144 end:
%p A195144 P:=proc(j)
%p A195144 local h,m,n,r;
%p A195144 for m from 3 to j  do
%p A195144   h:=0;
%p A195144   for r from 2 to m-1 do
%p A195144     if abs((m mod r)-r/2)<1 then h:=h+Rev(r); print(r); fi;
%p A195144   od;
%p A195144   if h=Rev(m) then print(m); fi;
%p A195144 od;
%p A195144 end:
%p A195144 P(1000000);
%Y A195144 Cf. A066272, A069942.
%K A195144 nonn,hard,base,bref,more
%O A195144 1,1
%A A195144 _Paolo P. Lava_ and _Donovan Johnson_, Sep 12 2011