cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

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%I A095417 #11 Apr 29 2022 20:51:28
%S A095417 0,2,13,4,15,26,37,25,41,36,45,47,62,67,57,67,60,92,19,76,116,99,23,
%T A095417 105,63,120,124,134,133,110,140,155,141,130,132,168,137,103,184,176,
%U A095417 182,226,188,217,168,145,186,220,245,170,221,228,232,267,216,225,179,259
%N A095417 Sum of all decimal digits of distinct prime factors for n-th repunit.
%H A095417 Max Alekseyev, <a href="/A095417/b095417.txt">Table of n, a(n) for n = 1..352</a> (first 322 terms from Giovanni Resta)
%F A095417 a(n) = A095402(A002275(n)).
%e A095417 n=60: concatenated distinct-prime factor-set for 60th-repunit is:
%e A095417 371113313741611012112412712161354190919901279612906161418890139526741,
%e A095417 its digit sum=a(60)=244.
%t A095417 a[1]=0; a[n_] := Total[ Flatten[ IntegerDigits /@ First /@ FactorInteger[(10^n - 1)/9]]]; Array[a, 60] (* _Giovanni Resta_, Jul 19 2018 *)
%Y A095417 Cf. A095402, A002275, A095370, A095413-A095418.
%K A095417 base,nonn
%O A095417 1,2
%A A095417 _Labos Elemer_, Jun 22 2004
%E A095417 Data corrected by _Giovanni Resta_, Jul 19 2018