a(1) = 1; for n > 1, a(n) = smallest integer > a(n-1) such that a(n)*a(i)+1 is semiprime for all 1 <= i <= n-1.
A219953
a(1) = 1; for n > 1, a(n) = smallest integer > a(n-1) such that a(n)*a(i)+1 is semiprime for all 1 <= i <= n-1.
Terms
- a(0) =1a(1) =3a(2) =8a(3) =38a(4) =86a(5) =318a(6) =504a(7) =3600a(8) =8132a(9) =83160a(10) =116850a(11) =202272a(12) =399126a(13) =6190086a(14) =8756916a(15) =25253676a(16) =309709400a(17) =1112878446a(18) =1478724036a(19) =11062089360a(20) =97331025386
External references
- oeis: A219953