OFFSET
1,1
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000
EXAMPLE
28 = 2 + 3 + 5 + 7 + 11.
MATHEMATICA
f[n_]:=Prime[n]+Prime[n+1]+Prime[n+2]+Prime[n+3]+Prime[n+4]; Select[Table[f[n], {n, 9!}], IntegerQ[Sqrt[1+8# ]]&]
Select[Total/@Partition[Prime[Range[50000]], 5, 1], OddQ[Sqrt[1+8#]]&] (* Harvey P. Dale, Feb 08 2020 *)
PROG
(Magma) [ t: n in [1..28000] | IsSquare(8*t+1) where t is &+[NthPrime(n+s): s in [0..4]] ]; // Bruno Berselli, Apr 28 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Feb 18 2010
STATUS
approved