OFFSET
1,1
COMMENTS
Conjecture: this sequence and A064397 are disjoint. That is to say, prime(n) + prime(n+1) and prime(n) + prime(n+1) + prime(n+2) + prime(n+3) cannot be squares at the same time. - Jianing Song, Nov 13 2022
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..200 from Harvey P. Dale)
FORMULA
EXAMPLE
a(1) = 3 because prime(3) + prime(4) + prime(5) + prime(6) = 5+7+11+13 = 36 = 6*6.
MATHEMATICA
Flatten[Position[Partition[Prime[Range[70000]], 4, 1], _?(IntegerQ[ Sqrt[ Total[ #]]]&), {1}, Heads->False]] (* Harvey P. Dale, Dec 09 2015 *)
PROG
(PARI) lista(m) = {for (n = 1, m, if (issquare(prime(n) + prime(n+1) + prime(n+2) + prime(n+3)), print1(n, ", ")); ); } \\ Michel Marcus, Apr 19 2013
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Zak Seidov, Jun 21 2003
EXTENSIONS
Definition corrected by Zak Seidov, Dec 13 2014
STATUS
approved