A144364 Where records occur in A144261.

1, 11, 31, 53, 331, 377, 983, 1499, 2609, 3329, 6637, 6997, 19937, 34987, 157961, 173699, 256661, 1349923, 1616359, 1993333, 2199833, 5794969, 6906869, 12204431, 14223073, 20666551, 168499997, 4819002127, 7331752277, 8259275501, 27017515331, 27581017543

Offset: 1

Author

Klaus Brockhaus, Sep 19 2008

Keywords

• base
• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..39

Crossrefs

Cf. A005349 (Niven numbers), A144261 (smallest k such that k*n is a Niven number), A144363 (records in A144261).

Programs

Mathematica

f[n_] := Module[{k = 1, m = n}, While[!Divisible[m, DigitSum[m]], m +=n; k++]; k]; seq[lim_] := Module[{s = {}, fm = 0, fi}, Do[fi = f[i]; If[fi > fm, fm = fi; AppendTo[s, i]], {i, 1, lim}]; s]; seq[10^5] (* Amiram Eldar, Jun 30 2025 *)

PARI

f(n) = {my(k = 1, m = n); while(m % sumdigits(m), m +=n; k++); k;}
list(lim) = my(fm = 0, fi); for(i = 1, lim, fi = f(i); if(fi > fm, fm = fi; print1(i, ", "))); \\ Amiram Eldar, Jun 30 2025

Extensions

a(27)-a(30) from Donovan Johnson, Jul 20 2010

a(31)-a(32) from Amiram Eldar, Jun 30 2025