Proof:
(1) Since 2an+1−an=n(n+1)(n+2)n−2, bn=an−n(n+1)1,
we have an+1=21an+2n(n+1)(n+2)n−2.
Therefore, bnbn+1=an−n(n+1)121an+2n(n+1)(n+2)n−2−(n+1)(n+2)1=an−n(n+1)121an−21×n(n+1)1=21.
Therefore, {bn} is a geometric sequence with a common ratio of 21, and the first term is a1−21=21.
Thus, bn=(21)n.
Hence, an=(21)n+n(n+1)1.
(2) Cn=nbn=n×(21)n.
Therefore, Tn=21+2×221+3×231+…+n×2n1,
21Tn=221+2×231+…+(n−1)×2n1+n×2n+11.
Thus, 21Tn=21+(21)2+…+(21)n−n×2n+11=1−2121(1−2n1)−n×2n+11=1−2n+12+n.
Therefore, Tn=2−2n2+n<2.
Thus, we conclude that Tn<2 with Tn<2.