A050218 Sums of digits of Smith numbers A006753.

4, 4, 9, 13, 13, 13, 4, 13, 4, 13, 13, 13, 13, 13, 18, 13, 13, 15, 13, 15, 13, 13, 13, 13, 18, 21, 15, 13, 15, 15, 18, 15, 15, 18, 15, 13, 17, 18, 15, 22, 15, 15, 15, 22, 13, 15, 13, 22, 22, 15, 4, 13, 13, 13, 13, 15, 17, 18, 13, 15, 15, 13, 13, 22, 17, 18, 21, 22, 13, 15

Offset

1,1

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Smith Number.

Wikipedia, Smith number.

Formula

a(n) = A007953(A006753(n)).

Mathematica

d[n_]:=IntegerDigits[n]; tr[n_]:=Transpose[FactorInteger[n]]; t={}; Do[If[!PrimeQ[n]&&(x=Total[d[n]])==Total[d@tr[n][[1]]*tr[n][[2]], 2], AppendTo[t, x]], {n, 4, 1850}]; t (* Jayanta Basu, Jun 04 2013 *)

Crossrefs

Cf. A006753, A050219, A050220.

Cf. A202388, A050223.

Sequence in context: A088190 A092322 A341678 * A165996 A266008 A284628

Adjacent sequences: A050215 A050216 A050217 * A050219 A050220 A050221

Keyword

nonn,base,less

Author

Eric W. Weisstein

Extensions

Offset corrected by Reinhard Zumkeller, Dec 19 2011

Status

approved