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

 

Logo

Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A176638 Partial sums of A018190. 0
1, 2, 5, 12, 34, 115, 446, 1881, 8386, 38472, 179701, 849285, 4047541, 19415118, 93623028, 453486806, 2205081449, 10758731196, 52651373968, 258365785954, 1270930958357, 6265738653554, 30952863554094, 153191072337297 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Partial sums of number of planar simply-connected polyhexes (or benzenoid hydrocarbons) with n hexagons. The only known primes in the partial sum are 2 and 5.

LINKS

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

FORMULA

a(n) = SUM[i=1..n] A018190(i).

EXAMPLE

a(6) = 1 + 1 + 3 + 7 + 22 + 81 = 115.

CROSSREFS

Cf. A000228, A002216, A018190, A038142-A038147.

Sequence in context: A032292 A151408 A121956 * A131467 A000103 A101292

Adjacent sequences:  A176635 A176636 A176637 * A176639 A176640 A176641

KEYWORD

nonn

AUTHOR

Jonathan Vos Post, Apr 22 2010

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 3 05:29 EST 2020. Contains 338899 sequences. (Running on oeis4.)