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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A122140 Numbers n such that n divides sum of cubes of the first n primes A098999(n). 5
1, 25, 537, 661, 5199, 113253, 240621, 5337048977, 17434578479, 34216676921 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(9) > 6*10^9. - Donovan Johnson, Oct 15 2012

a(11) > 10^11. - Robert Price, Mar 29 2013

LINKS

Table of n, a(n) for n=1..10.

OEIS Wiki, Sums of powers of primes divisibility sequences.

EXAMPLE

a(2) = 25 because 25 is the first number n>1 that divides sum of cubes of the first n primes. Mod[ A098999[25], 25] = Mod[ 2^3 + 3^3 + 5^3 + ... + 89^3 + 97^3, 25 ] = 0.

MATHEMATICA

s = 0; t = {}; Do[s = s + Prime[n]^3; If[ Mod[s, n] == 0, AppendTo[t, n]], {n, 1000000}]; t

CROSSREFS

Sequence in context: A282689 A282874 A144942 * A083191 A226299 A264378

Adjacent sequences:  A122137 A122138 A122139 * A122141 A122142 A122143

KEYWORD

nonn

AUTHOR

Alexander Adamchuk, Aug 21 2006

EXTENSIONS

a(8) from Donovan Johnson, Oct 15 2012

a(9)-a(10) from Robert Price, Mar 29 2013

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified June 23 21:09 EDT 2018. Contains 311812 sequences. (Running on oeis4.)