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A280966 Happy numbers which when squared give another happy number. 1
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 (list; graph; refs; listen; history; text; internal format)
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: A064950 A240795 A058532 * A174466 A070422 A102574

Adjacent sequences:  A280963 A280964 A280965 * A280967 A280968 A280969

KEYWORD

nonn,base

AUTHOR

Sam Turley, Jan 11 2017

STATUS

approved

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Last modified July 21 22:02 EDT 2019. Contains 325210 sequences. (Running on oeis4.)