A078758 Term in A064389 (variation (4) of Recamán's sequence) where n appears, or 0 if n never appears.

1, 4, 2, 35, 33, 3, 5, 16, 14, 12, 10, 8, 6, 188, 58, 186, 184, 23, 25, 7, 9, 11, 13, 15, 17, 182, 48, 46, 50, 1774, 1770, 1772, 1786, 1784, 1766, 40, 1764, 32, 34, 36, 22, 20, 18, 24, 26, 204, 202, 200, 198, 196, 194, 192, 190, 1758, 1762, 1760, 79, 77, 1782, 602

Offset: 1

Author

Reiner Martin, Jan 08 2003

Keywords

• nonn

Comments

Is it ever 0?

If all a(n)>0, then this is the inverse permutation of A064389. - M. F. Hasler, Nov 03 2014

After 10^12 terms of A064389, the first unknown term of this sequence is 5191516. - Benjamin Chaffin, Oct 09 2016

Links

• Benjamin Chaffin, Table of n, a(n) for n = 1..20000 [First 6655 terms from Nick Hobson]
• Nick Hobson, Python program for this sequence
• Index entries for sequences related to Recamán's sequence
• Index entries for sequences that are permutations of the natural numbers

Crossrefs

Cf. A064389, A005132, A057167.

Programs

PARI

for(i=1,9e9,for(j=1,#a064389,a064389[j]==i&&print1(j",")+next(2));break) \\ The terms of A064389 must be stored in the vector a064389. - M. F. Hasler, Nov 03 2014