OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..1000
MATHEMATICA
happyQ[n_, b_] := NestWhile[Plus @@ (IntegerDigits[#, b]^2) &, n, UnsameQ, All] == 1; seqQ[b_] := happyQ[b, b] && AllTrue[Range[2, b - 1], ! happyQ[#, b] &]; Select[Range[2, 100], seqQ] (* Amiram Eldar, May 28 2020 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jud McCranie, Jun 20 2009
STATUS
approved