A113758 a(n) is the least number having sum of digits n in base 10 and also exactly n prime factors (counted with multiplicity).

10001, 12, 40, 32, 240, 3040, 2240, 1152, 6400, 12800, 21504, 440320, 2140160, 172032, 4710400, 1802240, 1327104, 20316160, 40632320, 17301504, 152043520, 602931200, 138412032, 117440512, 3607101440, 1132462080, 51204063232, 3355443200, 35232153600, 202400333824, 102005473280

Offset

2,1

Links

Table of n, a(n) for n=2..32.

Example

a(2)=10001 since 1+0+0+0+1=2 and 10001=73*137 has 2 prime factors.
a(3)=12 since 1+2=3 and 12=2*2*3 has 3 prime factors.

Mathematica

Lk[n_] := Block[{k = 2}, While[n != Plus @@ IntegerDigits[k] || n != Plus @@ (Transpose[FactorInteger@k][[2]]), k++ ]; k]; L = {}; Do[v = Lk[n]; Print[{n, v}]; AppendTo[L, v], {n, 2, 13}]; L

Crossrefs

Cf. A115156.

Sequence in context: A250440 A013857 A091566 * A273531 A291312 A203591

Adjacent sequences: A113755 A113756 A113757 * A113759 A113760 A113761

Keyword

base,nonn

Author

Giovanni Resta, Jan 18 2006

Extensions

a(23)-a(28) from Donovan Johnson, Nov 15 2009

a(29)-a(32) from Giovanni Resta, Mar 21 2017

Status

approved