A159305 - OEIS

%I #19 Jun 27 2018 03:19:57

%S 1,7,13,44,98950096,15832480722303616,1127444240280152749,

%T 80286250603180403871,271606440286606849984,3108406708580377597810,

%U 120346786571258131649185,1682555786678552786861430747564

%N Sequence of happy tribonacci numbers.

%C Intersection of A000073 and A007770. - _Michel Marcus_, Aug 08 2013

%H G. C. Greubel, <a href="/A159305/b159305.txt">Table of n, a(n) for n = 1..550</a>

%t hapQ[n_]:=MemberQ[NestList[Total[IntegerDigits[#]^2]&,n,15],1]; Select[ LinearRecurrence[{1,1,1},{1,1,2},150],hapQ] (* _Harvey P. Dale_, Jun 05 2011 *)

%K nonn,base

%O 1,2

%A Levrand Roland (roland.levrand(AT)gmx.ch), Apr 09 2009