A082547 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, 2, 2, 2, 4, 5, 9, 11, 16, 22, 26, 30, 38, 45, 51, 59, 68, 77, 83, 96, 106, 115, 127, 139, 151, 165, 177, 190, 204, 221, 236, 250, 267, 286, 304, 323, 339, 361, 382, 400, 421, 440, 465, 486, 512, 533, 556, 580, 604, 633, 656, 686, 713, 739, 769, 797, 827, 856

Offset

1,2

Links

Table of n, a(n) for n=1..58.

Example

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.

Prog

(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)

Crossrefs

Cf. A082533, A082534.

Sequence in context: A057591 A024405 A230381 * A068928 A326025 A278502

Adjacent sequences: A082544 A082545 A082546 * A082548 A082549 A082550

Keyword

easy,nonn

Author

Naohiro Nomoto, May 02 2003

Extensions

More terms from David Wasserman, Sep 16 2004

Status

approved