cp's OEIS Frontend

A045725 Fibonacci numbers having initial digit '1'.

%I A045725 #20 Feb 17 2024 10:32:18
%S A045725 1,13,144,1597,10946,17711,121393,196418,1346269,14930352,102334155,
%T A045725 165580141,1134903170,1836311903,12586269025,139583862445,
%U A045725 1548008755920,10610209857723,17167680177565,117669030460994,190392490709135,1304969544928657,14472334024676221,160500643816367088
%N A045725 Fibonacci numbers having initial digit '1'.
%t A045725 Select[Fibonacci[Range[2, 100]], IntegerDigits[#, 10][[1]] == 1 &] (* _T. D. Noe_, Nov 01 2006 *)
%o A045725 (PARI) select(x->(digits(x)[1] == 1), vector(85, n, fibonacci(n+1))) \\ _Michel Marcus_, Jan 30 2019
%o A045725 (Magma) [Fibonacci(n): n in [2..100] | Intseq(Fibonacci(n))[#Intseq(Fibonacci(n))] eq 1]; // _Vincenzo Librandi_, Jan 30 2019
%o A045725 (Scala) def fibonacci(n: BigInt): BigInt = {
%o A045725   val zero = BigInt(0)
%o A045725   def fibTail(n: BigInt, a: BigInt, b: BigInt): BigInt = n match {
%o A045725     case `zero` => a
%o A045725     case _ => fibTail(n - 1, b, a + b)
%o A045725   }
%o A045725   fibTail(n, 0, 1)
%o A045725 } // Tail recursion by Dario Carrrasquel
%o A045725 ((2 to 100).map(fibonacci(_))).filter(_.toString.startsWith("1")) // _Alonso del Arte_, Apr 22 2019
%Y A045725 Cf. A105501.
%Y A045725 Intersection of A000045 and A131835.
%K A045725 nonn,base
%O A045725 1,2
%A A045725 _Jeff Burch_
%E A045725 Corrected by _T. D. Noe_, Nov 01 2006