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.
%I A135101 #18 Jan 14 2024 12:30:40
%S A135101 1,2,3,10,15,24,55,46,71,116,101,180,213,196,205,276,307,444,337,610,
%T A135101 621,646,687,808,985,876,921,996,1049,1184,1417,1576,1665,1576,2127,
%U A135101 1836,2377,1660,2201,2088,2731,2844,2847,2944,3317,3232,3503,3294,3165
%N A135101 Digital sum (base the n-th prime) of n^n.
%H A135101 G. C. Greubel, <a href="/A135101/b135101.txt">Table of n, a(n) for n = 1..1000</a>
%F A135101 a(n) = ds_prime(n)(n^n), where ds_prime(n) = digital sum base the n-th prime.
%F A135101 a(n) = n^n - (prime(n)-1)*Sum{k>0} ( floor(n^n/prime(n)^k) ).
%e A135101 a(2) = ds_prime(2)(2^2) = ds_3(4) = 1+1 = 2;
%e A135101 a(10) = ds_prime(5)(5^5) = ds_11(3125) = 2+3+9+1 = 15.
%t A135101 Table[Total[IntegerDigits[n^n, Prime[n]]], {n, 50}] (* _G. C. Greubel_, Sep 23 2016 *)
%o A135101 (PARI) a(n) = vecsum(digits(n^n, prime(n))); \\ _Michel Marcus_, Sep 24 2016
%Y A135101 Cf. A000040, A000045, A007953, A054899, A075771, A131451, A133620, A133900, A134599.
%K A135101 nonn,base
%O A135101 1,2
%A A135101 _Hieronymus Fischer_, Dec 24 2007