block24.

> encode_abi(
  ["uint256", "uint256[]", "uint256"],
  [0xaaaa, [0xb1, 0xb2, 0xb3], 0xbbbb]
).hex()

/************* HEAD (32*3 bytes) *************/
// arg1: 0xaaaa
000000000000000000000000000000000000000000000000000000000000aaaa
// arg2: look at position 0x60 for array data
0000000000000000000000000000000000000000000000000000000000000060
// arg3: 0xbbbb
000000000000000000000000000000000000000000000000000000000000bbbb

/************* TAIL (128 bytes) *************/
// position 0x60. Data for arg2.
0000000000000000000000000000000000000000000000000000000000000003
00000000000000000000000000000000000000000000000000000000000000b1
00000000000000000000000000000000000000000000000000000000000000b2
00000000000000000000000000000000000000000000000000000000000000b3