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 A077648 #15 Oct 16 2024 22:26:30
%S A077648 2,3,5,7,1,1,1,1,2,2,3,3,4,4,4,5,5,6,6,7,7,7,8,8,9,1,1,1,1,1,1,1,1,1,
%T A077648 1,1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,
%U A077648 3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5
%N A077648 Initial digits of prime numbers.
%H A077648 Vincenzo Librandi, <a href="/A077648/b077648.txt">Table of n, a(n) for n = 1..10000</a>
%F A077648 a(n) = A000030(A000040(n)).
%t A077648 Table[First[IntegerDigits[Prime[n]]], {n, 1, 120}]
%o A077648 (Magma) [Intseq(p)[#Intseq(p)]: p in PrimesUpTo(600)]; // _Bruno Berselli_, Feb 14 2013
%o A077648 (PARI) a(n) = digits(prime(n))[1]; \\ _Michel Marcus_, Feb 11 2017
%o A077648 (Python)
%o A077648 from sympy import prime
%o A077648 def A077648(n): return int(str(prime(n))[0]) # _Chai Wah Wu_, Oct 16 2024
%Y A077648 Cf. A000030, A000040.
%K A077648 base,nonn
%O A077648 1,1
%A A077648 _Labos Elemer_, Nov 19 2002