1,2

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

Cf. A001273, A053612.

Sequence in context: A001273 A111524 A074346 this_sequence A102249 A062370 A069960

Adjacent sequences: A126970 A126971 A126972 this_sequence A126974 A126975 A126976

hard,nonn

Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), Mar 20 2007; corrected Mar 23 2007