a(2) = 1 as 1 = 1_2, which has 1 = 2  1 as its leading digit.
a(3) = 2 as 2 = 10_2 = 2_3, which have 1 = 2  1 and 2 = 3  1 as their leading digits.
a(4) = 54 as 54 = 110110_2 = 2000_3 = 312_4, which have 1 = 2  1, 2 = 3  1 and 3 = 4  1 as their leading digits.
a(5) = 13122 as 13122 = 11001101000010_2 = 200000000_3 = 3031002_4 = 404442_5, which have 1 = 2  1, 2 = 3  1, 3 = 4  1 and 4 = 5  1 as their leading digits.
a(6) = 15258789062500 as 15258789062500 = 110000010110110101100111010011101100100_2 = 2000000201121020121212112011_3 = 3132002312230322131210_4 = 4000000000000000000_5 = 52241442501204004_6, which have 1 = 2  1, 2 = 3  1, 3 = 4  1, 4 = 5  1 and 5 = 6  1 as their leading digits.
a(7) = 81582795696655426358720748526459181157825502882872103403434619627581986794626\
90448473536034793921827874140100908746255557234586263455831973302268738547817\
2585724832003163984432734404608 (Too large to include in the DATA section)
