login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A091522 Graham-Pollak sequence with initial term 5. 4
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 (list; graph; refs; listen; history; text; internal format)
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 6 13:45 EST 2021. Contains 349563 sequences. (Running on oeis4.)