A082533 - OEIS

%I #9 Oct 18 2019 04:07:07

%S 1,2,1,2,2,3,3,2,3,4,2,4,4,5,5,4,2,7,4,5,4,6,6,5,6,6,6,4,3,7,6,7,5,8,

%T 3,11,11,7,12,10,3,9,8,10,7,9,11,8,11,11,8,10,8,12,6,3,6,3,6,6,9,6,5,

%U 3,5,5,7,13,7,9,13,9,5,13,12,16,12,12,15,16,11,14,8,11,15,11,15,13,12,13,13

%N Number of primes p such that p can be expressed as the sum of consecutive primes with largest prime in the sum = n-th prime.

%e For n=10; 29 is the 10th prime. 29=29, 71=19+23+29, 101=13+17+19+23+29, 127=3+5+7+11+13+17+19+23+29. 29 and 71,101,127 are primes. so a(10)=4.

%t Table[Length[Select[Accumulate[Reverse[Table[Prime[i], {i, n}]]], PrimeQ]], {n, 91}] (* _Jayanta Basu_, Apr 21 2013 *)

%K easy,nonn

%O 1,2

%A _Naohiro Nomoto_, May 01 2003