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

5, 8, 895799

Offset: 1

Author

Paolo P. Lava and Donovan Johnson, Sep 12 2011

Keywords

• nonn
• hard
• base
• bref
• more

Comments

Like A069942 but using anti-divisors. No other terms up to 3*10^10.

Examples

			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.
		

Crossrefs

Cf. A066272, A069942.

Programs

Maple

Rev:=proc(n)
local a,i,k;
  i:=convert(n,base,10); a:=0;
  for k from 1 to nops(i) do a:=a*10+i[k]; od;
  a;
end:
P:=proc(j)
local h,m,n,r;
for m from 3 to j  do
  h:=0;
  for r from 2 to m-1 do
    if abs((m mod r)-r/2)<1 then h:=h+Rev(r); print(r); fi;
  od;
  if h=Rev(m) then print(m); fi;
od;
end:
P(1000000);