A241049 Smallest number k such that sopf(k)/digsum(k) = prime(n) where sopf(k) is the sum of the distinct primes dividing k and digsum(k) the sum of digits of k.

42, 104, 130, 10, 212, 1336, 1630, 1003, 1556, 3122, 2455, 5298, 9105, 13842, 3241, 5230, 10020, 8754, 11671, 10104, 16305, 13141, 7628, 12786, 16201, 2012, 18007, 10630, 11965, 12607, 13945, 14623, 38234, 24343, 30823, 24020, 7846, 17905, 11348, 12061, 27517

Offset

1,1

Comments

a(n) is the smallest k such that A008472(k)/ A007953(k) = prime(n).

Links

Michel Lagneau, Table of n, a(n) for n = 1..200

Example

a(7) = 1630 because A008472(1630)/ A007953(1630) = 170/10 = 17 = prime(7).

Mathematica

lst={}; Do[k=1; While[Plus @@ First[ Transpose[ FactorInteger[k]]]/
Plus@@IntegerDigits[k]!=Prime[n], k++]; AppendTo[lst, k], {n, 1, 42}]; lst

Crossrefs

Cf. A008472, A007953.

Sequence in context: A172465 A235109 A039470 * A075296 A023716 A045148

Adjacent sequences: A241046 A241047 A241048 * A241050 A241051 A241052

Keyword

nonn,base

Author

Michel Lagneau, Apr 15 2014

Status

approved