A105648 Smallest member of a set of Smith triples.

73615, 209065, 225951, 283745, 305455, 342879, 656743, 683670, 729066, 747948, 774858, 879221, 954590, 1185547, 1262722, 1353955, 1369374, 1495718, 1622495, 1666434, 1790480, 2197579, 2299772, 2428854, 2561678, 2576441, 2580367, 2636516, 2665480, 2707580, 2741816

Offset

1,1

Comments

If there are 3 consecutive numbers which are Smith numbers, these can be called a Smith triple.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

S. S. Gupta, Smith Numbers.

Example

a(1) = 73615 because 73615 is the smallest of 3 consecutive integers which are Smith numbers, i.e., the three consecutive numbers 73615, 73616, 73617 are all Smith numbers.

Mathematica

digSum[n_] := Plus @@ IntegerDigits[n]; smithQ[n_] := CompositeQ[n] && Plus @@ (Last@#*digSum[First@#] & /@ FactorInteger[n]) == digSum[n]; sm = smithQ /@ Range[3]; seq = {}; Do[sm = Join[Rest[sm], {smithQ[k]}]; If[And @@ sm, AppendTo[seq, k - 2]], {k, 4, 10^6}]; seq (* Amiram Eldar, Aug 18 2020 *)

Crossrefs

Cf. A006753, A050219, A059754, A105649, A105650.

Sequence in context: A242805 A250838 A365309 * A337740 A180300 A172640

Adjacent sequences: A105645 A105646 A105647 * A105649 A105650 A105651

Keyword

nonn,base

Author

Shyam Sunder Gupta, May 03 2005

Extensions

More terms from Amiram Eldar, Aug 18 2020

Status

approved