A061905 The iterative cycle: n -> sum of digits of n^2 has only two distinct elements.

7, 8, 13, 14, 16, 19, 22, 23, 24, 25, 27, 29, 31, 33, 34, 35, 36, 38, 41, 42, 46, 47, 52, 54, 55, 56, 57, 58, 59, 61, 65, 66, 68, 69, 70, 71, 72, 75, 78, 79, 80, 81, 84, 85, 95, 96, 99, 103, 104, 106, 108, 112, 115, 119, 121, 123, 129, 130, 131, 132, 135, 138, 139, 140

Offset

1,1

Comments

It seems that {10,1}, {13,16} and {9,18} are the only iterative cycles with 2 distinct elements.

Links

Table of n, a(n) for n=1..64.

Example

7 -> 4+9 = 13 -> 1+6+9 = 16 -> 2+5+6 = 13, thus only {13,16} are contained in the iterative cycle of 7. 24 -> 5+7+6 = 18 -> 3+2+4 = 9 -> 8+1 = 9, thus {18,9} are the only elements of the iterative cycle of 24.

Crossrefs

Cf. A007953, A004159, A061903 - A061910.

Sequence in context: A065729 A156605 A343298 * A308887 A308833 A025156

Adjacent sequences: A061902 A061903 A061904 * A061906 A061907 A061908

Keyword

nonn,base

Author

Asher Auel, May 17 2001

Status

approved