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A276591
a(n) is the smallest prime p > a(n-1) such that p - a(n-1) is an (n-1)-almost prime; a(1) = 2.
0
2, 5, 11, 19, 43, 151, 311, 439, 823, 2551, 6007, 12919, 23159, 35447, 92791, 203383, 535159, 731767, 1124983, 5253751, 6302327, 16919159, 32647799, 103426679, 160049783, 285878903, 386542199, 1066019447, 1468672631, 2676632183, 5092551287, 16366840439, 32472967799
OFFSET
1,1
EXAMPLE
a(2) - a(1) = 5 - 2 = 3, which is prime (a "1-almost prime");
a(3) - a(2) = 11 - 5 = 6 = 2*3, which is semiprime (2-almost prime).
CROSSREFS
Sequence in context: A121606 A166164 A097008 * A051653 A106015 A178316
KEYWORD
nonn
AUTHOR
Zak Seidov, Nov 16 2016
EXTENSIONS
a(32)-a(33) from Jinyuan Wang, Jul 31 2021
STATUS
approved