A069836 Inverse permutation to A057033: a(n) is the m such that A057033(m) = n, or 0 if no such m exists.

1, 4, 2, 13, 3, 7, 40, 22, 5, 10, 6, 12, 121, 31, 8, 67, 9, 16, 17, 364, 11, 19, 202, 37, 94, 49, 14, 24, 15, 25, 1093, 58, 112, 28, 18, 27, 52, 607, 20, 283, 21, 34, 32, 76, 23, 148, 62, 73, 157, 85, 26, 175, 38, 43, 3280, 337, 29, 46, 30, 42, 850, 103, 82, 45, 33, 1822

Offset: 1

Author

David Wasserman, Apr 23 2002

Keywords

• easy
• nonn

Comments

Are there any 0's in this sequence? I have computed that the first 1000 terms are all positive, the largest of these being a(980) = 1328602.

Examples

			a(4) = 13 because A057033(13) = 4.
		

Crossrefs

Cf. A057033.

Programs

MATLAB

function n = back_cyclic(n) i = 1; while i < n i = i + 1; if mod(n, i) == 0 n = n + i - 1; else n = n - 1; end end