A126973 a(n+1) is the smallest integer greater than a(n) such that the sum of the squares of its decimal digits is equal to a(n).

1, 10, 13, 23, 1233, 33999999999999999

Offset

1,2

Links

Table of n, a(n) for n=1..6.

Example

10 --> 1^2+0^2 = 1+0 =1
13 --> 1^2+3^2 = 1+9 = 10
23 --> 2^2+3^2 = 4+9 =13
1233 --> 1^2+2^2+3^3+3^2 = 1+4+9+9 = 23
33999999999999999 = 3^2*2 + 9^2*15 = 1233

Crossrefs

Cf. A001273, A053612.

Sequence in context: A001273 A111524 A074346 * A220045 A101215 A102249

Adjacent sequences: A126970 A126971 A126972 * A126974 A126975 A126976

Keyword

nonn,base

Author

Paolo P. Lava and Giorgio Balzarotti, Mar 20 2007; corrected Mar 23 2007

Extensions

Next term is greater than 10^419753086419753. [From Charles R Greathouse IV, Nov 13 2010]

Status

approved