A171865 Positions of 0's in A181391.

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

Author

N. J. A. Sloane, Oct 17 2010

Keywords

• nonn

Comments

A181391(a(n)) = 0; the sequence is infinite, proof by Jan Ritsema van Eck in comments in A181391.

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A181391, A171868.

Programs

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