|
| |
|
|
A111441
|
|
Numbers n such that the sum of the squares of the first n primes is divisible by n.
|
|
22
| |
|
|
1, 19, 37, 455, 509, 575, 20597, 202717, 1864637, 542474231, 1139733677
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
EXAMPLE
| The sum of the squares of the first 19 primes 2^2 + 3^2 + 5^2 + ... + 67^2 = 19*1314, thus 19 is in an element of the sequence.
|
|
|
MATHEMATICA
| s = 0; t = {}; Do[s = s + Prime[n]^2; If[ Mod[s, n] == 0, AppendTo[t, n]], {n, 10^8}]; t (* Robert G. Wilson v *)
|
|
|
PROG
| (MuPAD): a := 0; for n from 1 to 100000 do a := a + ithprime(n)^2; if a/n = trunc(a/n) then print(n); end_if; end_for;
|
|
|
CROSSREFS
| Cf. A045345.
Sequence in context: A050528 A053685 A136063 * A144594 A123028 A067205
Adjacent sequences: A111438 A111439 A111440 * A111442 A111443 A111444
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Stefan Steinerberger (hansibal(AT)hotmail.com), Nov 14 2005
|
|
|
EXTENSIONS
| a(8)&a(9) from Robert G. Wilson v (rgwv(at)rgwv.com), Nov 15 2005
2 more terms from Ryan Propper (rpropper(AT)stanford.edu), Mar 27 2007
|
| |
|
|
