Let b(n) = Product_{i=1..n} p_i/(p_i - 1), p_i = i-th prime; a(n) = minimum k such that b(k) >= n.

Terms

a(0) =0a(1) =0a(2) =1a(3) =2a(4) =4a(5) =6a(6) =9a(7) =14a(8) =22a(9) =35a(10) =55a(11) =89a(12) =142a(13) =230a(14) =373a(15) =609a(16) =996a(17) =1637a(18) =2698a(19) =4461a(20) =7398a(21) =12301a(22) =20503a(23) =34253a(24) =57348a(25) =96198a(26) =161659a(27) =272124a(28) =458789a(29) =774616