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Graham-Pollak sequence with initial term 5.
4

%I #17 Jan 23 2020 09:33:42

%S 5,7,10,14,20,28,40,57,81,115,163,231,327,463,655,927,1311,1854,2622,

%T 3708,5244,7416,10488,14832,20976,29665,41953,59331,83907,118663,

%U 167815,237326,335630,474653,671261,949307,1342523,1898614,2685046

%N Graham-Pollak sequence with initial term 5.

%H Seiichi Manyama, <a href="/A091522/b091522.txt">Table of n, a(n) for n = 1..500</a>

%H Th. Stoll, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL8/Stoll/stoll56.html">On Families of Nonlinear Recurrences Related to Digits</a>, Journal of Integer Sequences, Vol. 8 (2005), Article 05.3.2.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Graham-PollakSequence.html">Graham-Pollak Sequence</a>

%F a(n) = floor(sqrt(2) * (a(n-1) + 1/2)).

%t NestList[Floor[Sqrt[2](#+1/2)]&,5,40] (* _Harvey P. Dale_, Feb 24 2018 *)

%o (PARI) first(n)=my(v=vector(n)); v[1]=5; for(k=2,n, v[k]=sqrtint(2*(v[k-1]+1)*v[k-1])); v \\ _Charles R Greathouse IV_, Jan 23 2020

%Y Cf. A001521, A091523.

%K nonn

%O 1,1

%A _Eric W. Weisstein_, Jan 18 2004