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A105707 Smallest m such that 7 is at the n-th position of the decimal representation of the m-th Fibonacci number.

%I A105707 #22 Feb 16 2025 08:32:57
%S A105707 14,14,20,22,25,34,42,47,44,49,66,66,65,68,96,81,87,89,92,101,116,145,
%T A105707 111,116,129,153,132,135,167,159,159,156,159,168,175,176,178,183,217,
%U A105707 198,199,202,221,223,249,223,226,235,266,243,245,250,258,265,266,269
%N A105707 Smallest m such that 7 is at the n-th position of the decimal representation of the m-th Fibonacci number.
%C A105707 Positions start with the 0th position on the right. - _Robert Israel_, Jun 01 2020
%H A105707 Robert Israel, <a href="/A105707/b105707.txt">Table of n, a(n) for n = 0..2000</a>
%H A105707 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/FibonacciNumber.html">Fibonacci Number</a>
%F A105707 A000045(a(n)) = A105717(n).
%e A105707 n=3: a(3)=22, A000045(22) = A105710(3) = 17711 -> 1[7]711;
%e A105707 n=4: a(4)=25, A000045(25) = A105710(4) = 75025 -> [7]5025.
%p A105707 N:= 100: # for a(0) to a(N)
%p A105707 F[0]:= 0: F[1]:= 1:
%p A105707 V:= Array(0..N):
%p A105707 count:= 0:
%p A105707 for m from 2 while count < N+1 do
%p A105707   F[m]:= F[m-1]+F[m-2];
%p A105707   L:= convert(F[m],base,10);
%p A105707   M:= select(t -> L[t+1]=7 and V[t]=0, [$0..min(N,nops(L)-1)]);
%p A105707   count:= count + nops(M);
%p A105707   V[M]:= m;
%p A105707 od:
%p A105707 convert(V,list); # _Robert Israel_, Jun 01 2020
%Y A105707 Cf. A105701, A072354, A105702, A105703, A105704, A105705, A105706, A105708, A105709.
%K A105707 nonn,base
%O A105707 0,1
%A A105707 _Reinhard Zumkeller_, Apr 18 2005