OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..500
EXAMPLE
a(1) = 3 because prime(1) + prime(2) - 2 = 2 + 3 - 2 = 3 = T(2);
a(2) = 6 because prime(2) + prime(3) - 2 = 3 + 5 - 2 = 6 = T(3);
a(5) = 66 because prime(11) + prime(12) - 2 = 31 + 37 - 2 = 66 = T(11);
a(6) = 136 because prime(19) + prime(20) - 2 = 67 + 71 - 2 = 136 = T(16).
MATHEMATICA
Select[Table[Prime[n] + Prime[n + 1] - 2, {n, 7000}], IntegerQ[Sqrt[1 + 8# ]] &] (* Ray Chandler, Oct 07 2005 *)
Select[Total[#]-2&/@Partition[Prime[Range[10000]], 2, 1], OddQ[ Sqrt[ 8#+1]]&] (* Harvey P. Dale, Sep 03 2016 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Sep 20 2005
EXTENSIONS
Edited and extended by Ray Chandler, Oct 07 2005
STATUS
approved