A056529 Number of iterations of sum of digits of square to reach 1, 9, 13 or 16.

0, 3, 1, 2, 2, 1, 1, 2, 0, 1, 3, 1, 0, 1, 1, 0, 3, 1, 2, 3, 1, 1, 1, 2, 1, 3, 2, 3, 1, 1, 1, 2, 2, 1, 2, 2, 3, 1, 1, 2, 1, 2, 2, 3, 1, 2, 1, 1, 2, 2, 1, 1, 3, 2, 2, 1, 2, 1, 1, 1, 1, 3, 3, 3, 1, 2, 2, 1, 2, 1, 2, 2, 3, 2, 2, 2, 2, 2, 1, 2, 2, 3, 2, 2, 1, 2, 3, 2, 3, 1, 3, 2, 3, 2, 1, 2, 2, 3, 2, 1, 3, 1, 1, 1, 1

Offset: 1

Author

Henry Bottomley, Jun 19 2000

Keywords

• base
• easy
• nonn

Examples

			a(2)=3 because successive iterations give 2 -> 4 -> 7 -> 13 -> 16 -> 13 etc.
		

Crossrefs

Cf. A004159 for sum of digits of square, A056528 for two iterations, A056020 where iteration settles to 1, A056020 where iteration settles to 9, A056527 where iteration settles to 13 and 16.