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

14, 14, 20, 22, 25, 34, 42, 47, 44, 49, 66, 66, 65, 68, 96, 81, 87, 89, 92, 101, 116, 145, 111, 116, 129, 153, 132, 135, 167, 159, 159, 156, 159, 168, 175, 176, 178, 183, 217, 198, 199, 202, 221, 223, 249, 223, 226, 235, 266, 243, 245, 250, 258, 265, 266, 269

Offset

0,1

Comments

Positions start with the 0th position on the right. - Robert Israel, Jun 01 2020

Links

Robert Israel, Table of n, a(n) for n = 0..2000

Eric Weisstein's World of Mathematics, Fibonacci Number

Formula

A000045(a(n)) = A105717(n).

Example

n=3: a(3)=22, A000045(22) = A105710(3) = 17711 -> 1[7]711;
n=4: a(4)=25, A000045(25) = A105710(4) = 75025 -> [7]5025.

Maple

N:= 100: # for a(0) to a(N)
F[0]:= 0: F[1]:= 1:
V:= Array(0..N):
count:= 0:
for m from 2 while count < N+1 do
  F[m]:= F[m-1]+F[m-2];
  L:= convert(F[m], base, 10);
  M:= select(t -> L[t+1]=7 and V[t]=0, [$0..min(N, nops(L)-1)]);
  count:= count + nops(M);
  V[M]:= m;
od:
convert(V, list); # Robert Israel, Jun 01 2020

Crossrefs

Cf. A105701, A072354, A105702, A105703, A105704, A105705, A105706, A105708, A105709.

Sequence in context: A010853 A291510 A186128 * A325602 A157427 A003905

Adjacent sequences: A105704 A105705 A105706 * A105708 A105709 A105710

Keyword

nonn,base

Author

Reinhard Zumkeller, Apr 18 2005

Status

approved