OFFSET
1,1
COMMENTS
FORMULA
EXAMPLE
a(1)=1-2+3=2. a(2)=5. a(3)=9-10+11=10. a(4)=13-14+15-16+17=15. a(5)=17-18+19-20+21-22+23-24+25-26+27-28+29=23.
MAPLE
MATHEMATICA
p := Select[Prime[Range[280]], PrimeQ[# + 2] &]; Table[(p[[n]] + 4*n - 3)/2, {n, Length[p]}] (* L. Edson Jeffery, Dec 14 2014 (after Robert G. Wilson v) *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Jul 20 2009
EXTENSIONS
a(5) and a(23)-a(25) corrected by R. J. Mathar, Aug 02 2009
STATUS
approved