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A280966 Happy numbers which when squared give another happy number. 1

%I

%S 1,7,10,28,70,91,100,167,236,280,329,379,397,638,655,656,700,709,836,

%T 899,910,1000,1067,1114,1177,1212,1288,1299,1332,1444,1447,1528,1547,

%U 1574,1587,1670,1679,1717,1727,1733,1745,1748,1752,1758,1814,1844,1851,2109

%N Happy numbers which when squared give another happy number.

%C If x is a member then so is 10*x. - _Robert Israel_, Jan 25 2017

%H Robert Israel, <a href="/A280966/b280966.txt">Table of n, a(n) for n = 1..10000</a>

%p ishappy:= proc(n) option remember;

%p procname(convert(map(`^`,convert(n,base,10),2),`+`))

%p end proc:

%p ishappy(1):= true:

%p ishappy(37):= false:

%p select(t -> ishappy(t) and ishappy(t^2), [$1..10000]); # _Robert Israel_, Jan 25 2017

%Y Cf. A007770.

%K nonn,base

%O 1,2

%A _Sam Turley_, Jan 11 2017

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Last modified October 21 20:44 EDT 2019. Contains 328315 sequences. (Running on oeis4.)