A235267 Places n such that 1 + q!/p! is prime, where p = prime(n) and q = prime(n + 1).

3, 5, 33, 35, 43, 69, 86, 106, 108, 116, 124, 127, 171, 174, 182, 200, 201, 238, 255, 256, 270, 271, 277, 294, 310, 318, 323, 332, 356, 384, 388, 390, 392, 397, 398, 402, 409, 469, 494, 495, 520, 542, 551, 562, 572, 582, 606, 632, 633, 645, 649, 652, 671, 672

Offset

1,1

Links

K. D. Bajpai, Table of n, a(n) for n = 1..1510

Example

3 is in the sequence because (prime(3)! + prime(4)!)/prime(3)! =  (5! + 7!)/5! = (120 + 5040)/120 =  43 which is prime.

Maple

isA235267 := proc(n)
    local p, q ;
    p := ithprime(n) ;
    q := nextprime(p) ;
    if isprime(1+q!/p!) then
        true;
    else
        false;
    end if;
end proc:
for n from 1 do
    if isA235267(n) then
        print(n) ;
    end if;
end do:

Crossrefs

Cf. A000040, A100858.

Sequence in context: A179387 A295364 A199774 * A284379 A372718 A103010

Adjacent sequences: A235264 A235265 A235266 * A235268 A235269 A235270

Keyword

nonn

Author

K. D. Bajpai, Jan 05 2014

Status

approved