A091522 Graham-Pollak sequence with initial term 5.

5, 7, 10, 14, 20, 28, 40, 57, 81, 115, 163, 231, 327, 463, 655, 927, 1311, 1854, 2622, 3708, 5244, 7416, 10488, 14832, 20976, 29665, 41953, 59331, 83907, 118663, 167815, 237326, 335630, 474653, 671261, 949307, 1342523, 1898614, 2685046

Offset

1,1

Links

Seiichi Manyama, Table of n, a(n) for n = 1..500

Th. Stoll, On Families of Nonlinear Recurrences Related to Digits, Journal of Integer Sequences, Vol. 8 (2005), Article 05.3.2.

Eric Weisstein's World of Mathematics, Graham-Pollak Sequence

Formula

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

Mathematica

NestList[Floor[Sqrt[2](#+1/2)]&, 5, 40] (* Harvey P. Dale, Feb 24 2018 *)

Prog

(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

Crossrefs

Cf. A001521, A091523.

Sequence in context: A190035 A071911 A070875 * A020711 A183044 A133756

Adjacent sequences: A091519 A091520 A091521 * A091523 A091524 A091525

Keyword

nonn

Author

Eric W. Weisstein, Jan 18 2004

Status

approved