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

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A305265 a(n) = 12*2^n + 62. 4
74, 86, 110, 158, 254, 446, 830, 1598, 3134, 6206, 12350, 24638, 49214, 98366, 196670, 393278, 786494, 1572926, 3145790, 6291518, 12582974, 25165886, 50331710, 100663358, 201326654, 402653246, 805306430, 1610612798, 3221225534, 6442451006, 12884901950, 25769803838, 51539607614, 103079215166, 206158430270 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

a(n) (n>=1) is the number of vertices of the first type of dendrimer nanostar G[n], shown pictorially in the Iranmanesh et al. reference (Fig. 1).

LINKS

Colin Barker, Table of n, a(n) for n = 0..1000

A. Iranmanesh, N. A. Gholami, Computing the Szeged index of two type dendrimer nanostars, Croatica Chemica Acta, 81, No. 2, 2008, 299-303.

Index entries for linear recurrences with constant coefficients, signature (3,-2).

FORMULA

From Colin Barker, May 30 2018: (Start)

G.f.: 2*(37 - 68*x) / ((1 - x)*(1 - 2*x)).

a(n) = 3*a(n-1) - 2*a(n-2) for n>1.

(End)

MAPLE

seq(12*2^n+62, n = 0..40);

PROG

(PARI) Vec(2*(37 - 68*x) / ((1 - x)*(1 - 2*x)) + O(x^40)) \\ Colin Barker, May 30 2018

CROSSREFS

Cf. A305266, A305267, A305268.

Sequence in context: A136948 A137139 A095569 * A055111 A020203 A295158

Adjacent sequences:  A305262 A305263 A305264 * A305266 A305267 A305268

KEYWORD

nonn,easy

AUTHOR

Emeric Deutsch, May 29 2018

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 January 18 16:27 EST 2020. Contains 331011 sequences. (Running on oeis4.)