OFFSET
1,2
COMMENTS
Can anybody prove or disprove a(n) = O(n^c) for some constant c?
Jonathan Vos Post has observed that every term in A076768 also occurs in this sequence.
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..10000
EXAMPLE
7 = 1+6 = 2+5 = 3+4; 7 is in the sequence because there is no sum where the first element is a prime and the second one a triangular number.
MATHEMATICA
lim=6000; plim=PrimePi[lim]; tlim=Ceiling[Sqrt[2lim]]; Complement[Range[lim], Union[Flatten[Table[Prime[i]+PolygonalNumber[j], {i, plim}, {j, tlim}]]]] (* James C. McMahon, Jun 04 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Stefan Steinerberger, Nov 25 2005
EXTENSIONS
a(47) and offset corrected by Donovan Johnson, Feb 09 2013
STATUS
approved