Concatenating n with n+1 (in base 10) gives a number which is the product of 2 palindromes.

Terms

a(0) =1a(1) =4a(2) =5a(3) =115a(4) =148a(5) =247a(6) =346a(7) =371a(8) =445a(9) =528a(10) =7606a(11) =8376a(12) =9157a(13) =12478a(14) =16528a(15) =19834a(16) =22477a(17) =25103a(18) =28546a(19) =31989a(20) =32476a(21) =33057a(22) =38875a(23) =40495a(24) =42475a(25) =45761a(26) =46335a(27) =50494a(28) =52474a(29) =52647