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A050218 Sums of digits of Smith numbers A006753. 4
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
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
Sequence in context: A088190 A092322 A341678 * A165996 A266008 A284628
KEYWORD
nonn,base,less
AUTHOR
EXTENSIONS
Offset corrected by Reinhard Zumkeller, Dec 19 2011
STATUS
approved

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Last modified February 21 02:30 EST 2024. Contains 370219 sequences. (Running on oeis4.)