A288517 Least integer k such that A001358(k) + A001358(k+1) is the product of exactly n prime factors (counting multiplicity).

3, 1, 28, 4, 19, 39, 48, 89, 120, 551, 447, 589, 3707, 10137, 21644, 28456, 22998, 44494, 86132, 166930, 703448, 628371, 1220814, 1608668, 11153853, 6091437, 56676014, 268389220, 146153797, 193010987, 916382785, 738246947, 4702317172, 2830095027, 12627951809

Offset

1,1

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..50

Example

n=1: k=3, A001358(3) + A001358(4) = 9 + 10 = 19 = A000040(8) (8th prime),
n=2: k=1, A001358(1)+A001358(2) = 4+6 = 10 = 2*5 = A001358(4) (4th semiprime),
n=11: k=447, A001358(447)+A001358(448) = 1535+1537 = 3072 = 2^10*3 = A069272(2) (2nd 11-almost prime).

Crossrefs

Cf. A000040, A001358, A014612, A014614, A046306, A046308, A046310, A046312, A046314, A069272.

Sequence in context: A260902 A165624 A287206 * A188110 A358165 A298399

Adjacent sequences: A288514 A288515 A288516 * A288518 A288519 A288520

Keyword

nonn

Author

Zak Seidov, Jun 10 2017

Extensions

a(21)-a(35) from Charles R Greathouse IV, Jun 10 2017

Status

approved