A280966 Happy numbers which when squared give another happy number.

1, 7, 10, 28, 70, 91, 100, 167, 236, 280, 329, 379, 397, 638, 655, 656, 700, 709, 836, 899, 910, 1000, 1067, 1114, 1177, 1212, 1288, 1299, 1332, 1444, 1447, 1528, 1547, 1574, 1587, 1670, 1679, 1717, 1727, 1733, 1745, 1748, 1752, 1758, 1814, 1844, 1851, 2109

Offset

1,2

Comments

If x is a member then so is 10*x. - Robert Israel, Jan 25 2017

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

ishappy:= proc(n) option remember;
   procname(convert(map(`^`, convert(n, base, 10), 2), `+`))
end proc:
ishappy(1):= true:
ishappy(37):= false:
select(t -> ishappy(t) and ishappy(t^2), [$1..10000]); # Robert Israel, Jan 25 2017

Crossrefs

Cf. A007770.

Sequence in context: A240795 A058532 A370107 * A360430 A174466 A070422

Adjacent sequences: A280963 A280964 A280965 * A280967 A280968 A280969

Keyword

nonn,base

Author

Sam Turley, Jan 11 2017

Status

approved