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Number of primes p such that p can be expressed as the sum of distinct primes with largest prime in the sum = n-th prime.
1

%I #5 Mar 31 2012 13:50:44

%S 1,2,2,2,4,5,9,11,16,22,26,30,38,45,51,59,68,77,83,96,106,115,127,139,

%T 151,165,177,190,204,221,236,250,267,286,304,323,339,361,382,400,421,

%U 440,465,486,512,533,556,580,604,633,656,686,713,739,769,797,827,856

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

%e For n=5; 11 is the 5th prime. 11=11, 13= 2+11, 19= 3+5+11, 23= 2+3+7+11 = 5+7+11. 11 and 13,19,23 are primes. so a(5)=4.

%o (PARI) limit = 70; M = sum(i = 1, limit, prime(i)); v = vector(M); primeSum = 0; forprime (n = 1, prime(limit), count = 1; forstep (i = primeSum, 1, -1, if (v[i], if (isprime(i + n), count = count + 1); v[i + n] = 1)); v[n] = 1; print(count); primeSum = primeSum + n)

%Y Cf. A082533, A082534.

%K easy,nonn

%O 1,2

%A _Naohiro Nomoto_, May 02 2003

%E More terms from _David Wasserman_, Sep 16 2004