

A193995


Maximum number of terms required to determine whether a number is happy or not (A007770 or A031177).


2



1, 9, 13, 8, 12, 17, 6, 13, 12, 2, 10, 13, 3, 14, 11, 8, 13, 11, 5, 8, 13, 14, 4, 9, 11, 10, 14, 4, 10, 13, 3, 4, 12, 12, 13, 16, 8, 10, 13, 9, 14, 8, 12, 5, 15, 12, 11, 14, 5, 12, 11, 11, 13, 15, 13, 10, 12, 8, 10, 17, 9, 10, 16, 12, 10, 15, 10, 3, 13, 6
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OFFSET

1,2


COMMENTS

The number 1 is the only term requiring just one term to determine if it is happy. Although the bfile appears to show that there are only a few numbers having 8 terms, see A193996 for more beginning at 78999.


LINKS



EXAMPLE

For n=2, a(n)=9 because the iterations are 2, 4, 16, 37, 58, 89, 145, 42, 20, 4, 16,...


MATHEMATICA

f[n_] := Total[IntegerDigits[n]^2]; Table[Length[NestWhileList[f, n, UnsameQ, All]]  1, {n, 100}]


CROSSREFS



KEYWORD

nonn,base


AUTHOR



STATUS

approved



