A094406 Smallest unhappy number that takes n steps to reach any of the unhappy cycle (4, 16, 37, 58, 89, 145, 42, 20) under iteration of sum of squares of digits map.

4, 2, 11, 15, 5, 3, 14, 45, 36, 6, 112, 269, 15999

Offset: 4

Author

Sergio Pimentel, Apr 30 2004

Keywords

• nonn
• base
• changed

Comments

This sequence is an analog of sequence A001273 with the unhappy numbers instead of the happy numbers.

The next term, 577999999999....999999999999 (199 digits) is too large to include.

Examples

			15 is the fourth term because: 15: 1^2 + 5^2 = 26 / 26: 2^2 + 6^2 = 40 / 40: 4^2 + 0^2 = 16 and 16 is a member of the unhappy number series (4, 16, 37, 58, 89, 145, 42, 20)
		

Links

• Michel Marcus, Table of n, a(n) for n = 4..17
• Walter Schneider, Unhappy Numbers.

Crossrefs

Cf. A001273.

Extensions

Edited by Charles R Greathouse IV, Aug 03 2010