A280379 a(n) = A056171(k) - m, where k=prime(n) and m is the Ramanujan prime index to the greatest Ramanujan prime R(m) <= k.

0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 2, 0, 1, 1, 2, 0, 0, 1, 1, 0, 1, 0, 0, 1, 2, 2, 3, 2, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 2, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0

Offset

1,30

Comments

a(n)=0 corresponds to the Ramanujan prime R_m = A104272(m) = A056171(k).

Links

Table of n, a(n) for n=1..79.

Formula

a(n) = A056171(k) - m, where k=prime(n) and m is the Ramanujan prime index to the greatest Ramanujan prime R_m = A104272(m) <= k.

Example

For prime(30)=113, A056171(113) = 14, 107 is R_12 and 127 is R_13, so 14 -12 = 2 (first occurrence).

Prog

(PARI) \\RR[x] is a list of Ramanujan primes, A104272.
{plimit=1.1*10^4; n=s=0;
forprime(p=2, plimit,
    s++;
    if(p==RR[n+1], n++);
    print1(s-primepi(floor(p/2))-n, ", ");
    )
}

Crossrefs

Cf. A056171, A104272.

Sequence in context: A219987 A077614 A336396 * A375537 A333307 A180793

Adjacent sequences: A280376 A280377 A280378 * A280380 A280381 A280382

Keyword

nonn

Author

John W. Nicholson, Jan 01 2017

Status

approved