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 A261607 #28 Aug 26 2025 09:02:33
%S A261607 0,1,1,2,3,5,8,13,21,34,55,1,2,3,6,10,16,26,43,1,1,3,4,7,12,20,33,54,
%T A261607 1,2,3,6,10,16,26,42,1,1,3,4,7,12,20,33,54,1,2,3,6,10,16,26,42,1,1,2,
%U A261607 4,7,12,20,33,53,1,2,3,6,9,16,25,42,1,1,2,4,7,12
%N A261607 Initial digit of Fibonacci number F(n) in base 60.
%H A261607 Alois P. Heinz, <a href="/A261607/b261607.txt">Table of n, a(n) for n = 0..10000</a> (first 1001 terms from Reinhard Zumkeller)
%H A261607 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Sexagesimal.html">Sexagesimal</a>.
%H A261607 Wikipedia, <a href="http://www.wikipedia.org/wiki/Sexagesimal">Sexagesimal</a>.
%F A261607 a(n) = A261575(n, A261585(n)-1).
%F A261607 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Sum_{d=1..59} d*log(1+1/d)/log(60) = 13.92958... . - _Amiram Eldar_, Jan 12 2023
%F A261607 For n>9, a(n) = floor(60^{alpha*n-beta}), where alpha=log_60(phi), beta=log_60(5)/2, {x}=x-floor(x) denotes the fractional part of x, and phi = (1+sqrt(5))/2 = A001622. - _Hans J. H. Tuenter_, Aug 26 2025
%t A261607 IntegerDigits[Fibonacci[Range[0, 75]], 60][[All, 1]] (* _Michael De Vlieger_, Jan 22 2022 *)
%o A261607 (Haskell)
%o A261607 a261607 = last . a261575_row
%o A261607 (PARI) a(n) = if (n, digits(fibonacci(n), 60)[1], 0); \\ _Michel Marcus_, Jan 22 2022
%Y A261607 Cf. A000045, A261575, A261585, A261606, A008963, A001622.
%K A261607 nonn,look,base,changed
%O A261607 0,4
%A A261607 _Reinhard Zumkeller_, Sep 09 2015