Numbers k for which d(k-1) + d(k+1) is a record, where d(k) is the number of divisors of k.

Terms

a(0) =2a(1) =3a(2) =5a(3) =7a(4) =11a(5) =17a(6) =19a(7) =29a(8) =41a(9) =71a(10) =161a(11) =169a(12) =181a(13) =239a(14) =419a(15) =701a(16) =721a(17) =881a(18) =1079a(19) =1681a(20) =2159a(21) =2519a(22) =2521a(23) =4031a(24) =4159a(25) =5039a(26) =7561a(27) =8399a(28) =10081a(29) =13441