login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A161959 Smallest composite number which is the sum of n consecutive prime numbers. 0
8, 10, 26, 28, 56, 58, 77, 100, 129, 160, 236, 238, 326, 328, 381, 440, 501, 568, 639, 712, 791, 874, 963, 1060, 1161, 1264, 1371, 1480, 1593, 1720, 1851, 1988, 2127, 2276, 2427, 2584, 2747, 2914, 3087, 3266, 3447, 3638, 3831, 4028, 4227, 4438, 4661, 4888 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Table of n, a(n) for n=2..49.

FORMULA

a(2n+1) = A007504(2n+1)

a(2n) = A007504(2n) if that value is composite, else A007504(2n+1) - 2.

a(n) ~ n^2 * log(n) / 2.

EXAMPLE

a(6) = 56 = 3 + 5 + 7 + 11 + 13 + 17. (2 + 3 + 5 + 7 + 11 + 13 is prime so not a member of this sequence.)

MATHEMATICA

With[{prs=Prime[Range[500]]}, Table[SelectFirst[Total/@Partition[ prs, n, 1], CompositeQ], {n, 2, 50}]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 15 2019 *)

CROSSREFS

Sequence in context: A182405 A182366 A271313 * A236751 A259713 A096516

Adjacent sequences:  A161956 A161957 A161958 * A161960 A161961 A161962

KEYWORD

nonn

AUTHOR

Claudio Meller, Jun 22 2009

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 July 20 11:28 EDT 2019. Contains 325180 sequences. (Running on oeis4.)