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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A305574 Number of primitive (1,1) pairs in the Fibonacci tree at depth 3n. 0
5, 2, 7, 30, 143, 728, 3876, 21318, 120175, 690690, 4032015, 23841480, 142498692, 859515920, 5225264024, 31983672534, 196947587823, 1219199353190, 7583142491925, 47365474641870, 296983176369495, 1868545312633440, 11793499763070480, 74650344244967400 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

John Charles Saunders, Problems in Combinatorial and Analytic Number Theory, Ph. D. thesis, University of Waterloo, 2018.

LINKS

Table of n, a(n) for n=1..24.

Kevin G. Hare, and J. C. Saunders, On (a,b) Pairs in Random Fibonacci Sequences, Arxiv preprint arXiv:1608.03522 [math.NT], February 2018.

PROG

(PARI) {a(n) = my(A); if( n<=1, 5*(n==1), A = O(x); for(k=1, n, A = x / (1 - A)^2); polcoeff(A, n))}; /* Michael Somos, Dec 10 2019 */

CROSSREFS

Sequence in context: A198130 A309773 A241388 * A248259 A128666 A013674

Adjacent sequences:  A305571 A305572 A305573 * A305575 A305576 A305577

KEYWORD

nonn

AUTHOR

Jeffrey Shallit, Jun 05 2018

EXTENSIONS

More terms added and a(14) corrected by Michael Somos, Dec 10 2019

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 August 11 00:32 EDT 2020. Contains 336403 sequences. (Running on oeis4.)