A095417 Sum of all decimal digits of distinct prime factors for n-th repunit.

0, 2, 13, 4, 15, 26, 37, 25, 41, 36, 45, 47, 62, 67, 57, 67, 60, 92, 19, 76, 116, 99, 23, 105, 63, 120, 124, 134, 133, 110, 140, 155, 141, 130, 132, 168, 137, 103, 184, 176, 182, 226, 188, 217, 168, 145, 186, 220, 245, 170, 221, 228, 232, 267, 216, 225, 179, 259

Offset

1,2

Links

Max Alekseyev, Table of n, a(n) for n = 1..352 (first 322 terms from Giovanni Resta)

Formula

a(n) = A095402(A002275(n)).

Example

n=60: concatenated distinct-prime factor-set for 60th-repunit is:
371113313741611012112412712161354190919901279612906161418890139526741,
its digit sum=a(60)=244.

Mathematica

a[1]=0; a[n_] := Total[ Flatten[ IntegerDigits /@ First /@ FactorInteger[(10^n - 1)/9]]]; Array[a, 60] (* Giovanni Resta, Jul 19 2018 *)

Crossrefs

Cf. A095402, A002275, A095370, A095413-A095418.

Sequence in context: A338785 A335817 A093079 * A369587 A366719 A129733

Adjacent sequences: A095414 A095415 A095416 * A095418 A095419 A095420

Keyword

base,nonn

Author

Labos Elemer, Jun 22 2004

Extensions

Data corrected by Giovanni Resta, Jul 19 2018

Status

approved