The smallest pronic (A002378) with the same most significant digits as n.

Terms

a(0) =12a(1) =2a(2) =30a(3) =42a(4) =56a(5) =6a(6) =72a(7) =812a(8) =90a(9) =1056a(10) =110a(11) =12a(12) =132a(13) =1406a(14) =156a(15) =1640a(16) =1722a(17) =182a(18) =1980a(19) =20a(20) =210a(21) =2256a(22) =2352a(23) =240a(24) =2550a(25) =2652a(26) =272a(27) =2862a(28) =2970a(29) =30