A098324 Recurrence sequence based on positions of digits in decimal places of phi, the Golden Ratio = (1+sqrt(5))/2.
0, 4, 11, 34, 26, 67, 150, 1485, 2497, 8001, 2773, 16668, 39567, 80705, 15643, 19267, 29310, 223602, 2318795, 9376463, 7972671, 2412975, 3754694, 9560425, 1910435
Offset: 0
Examples
phi=1.61803398874989484820... So for example, a(2)=4 because 4th decimal place of phi is 0. a(3)=11 because 11th decimal place of phi is 4, a(4)=34 because 11 appears at the 34th to 35th decimal places and so on.
Crossrefs
Programs
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Maple
with(StringTools): Digits:=100000: G:=convert(evalf((1+sqrt(5))/2),string): a[0]:=0: for n from 1 to 17 do a[n]:=Search(convert(a[n-1],string), G)-2:printf("%d, ",a[n-1]):od: # Nathaniel Johnston, Apr 30 2011
Formula
a(1)=0, p(i)=position of first occurrence of a(i) in decimal places of phi, a(i+1)=p(i).
Extensions
a(17)-a(24) from Nathaniel Johnston, Apr 30 2011