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A171865
Positions of 0's in A181391.
12
1, 2, 4, 6, 11, 13, 18, 21, 25, 31, 36, 42, 45, 48, 53, 57, 60, 64, 67, 73, 82, 85, 90, 93, 99, 102, 106, 111, 117, 122, 126, 130, 135, 139, 143, 149, 153, 157, 163, 169, 174, 180, 184, 188, 197, 200, 203, 209, 213, 216, 226, 229, 233, 237, 243, 247, 252, 255, 258, 264, 270
OFFSET
1,2
COMMENTS
A181391(a(n)) = 0; the sequence is infinite, proof by Jan Ritsema van Eck in comments in A181391.
LINKS
PROG
(Haskell)
import Data.List (elemIndices)
a171865 n = a171865_list !! (n-1)
a171865_list = map (+ 1) $ elemIndices 0 a181391_list
-- Reinhard Zumkeller, Oct 31 2011
(Python)
A181391_list, A171865_list = [0, 0], [1, 2]
for n in range(1, 10**4):
for m in range(n-1, -1, -1):
if A181391_list[m] == A181391_list[n]:
A181391_list.append(n-m)
break
else:
A181391_list.append(0)
A171865_list.append(n+2) # Chai Wah Wu, Jan 02 2015
CROSSREFS
Sequence in context: A327309 A350668 A078198 * A398307 A372622 A344622
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Oct 17 2010
STATUS
approved