OFFSET
1,1
EXAMPLE
a(1) = 675, since 675 = 3^3 * 5^2 and 676 = 2^2 * 13^2 are the smallest products of at least 2 composite prime powers that differ by 1.
a(2) = 9800 since (3^4 * 11^2) - (2^3 * 5^2 * 7^2) = 1.
a(3) = 235224 since (5^2 * 97^2) - (2^3 * 3^5 * 11^2) = 1.
MATHEMATICA
nn = 2^36; s = Select[Rest@ Union@ Flatten@ Table[a^2*b^3, {b, nn^(1/3)}, {a, Sqrt[nn/b^3]}], ! PrimePowerQ[#] &]; Map[s[[#]] &, Position[Differences[s], 1][[All, 1]] ]
KEYWORD
nonn
AUTHOR
Michael De Vlieger, Nov 01 2022
STATUS
approved