Ask to generate letters plus numbers

There are 26 letters {A-Z} and 10 numbers {0-9}
If you want to generate 8-bit characters, the case-sensitive,
This arrangement is (26+26+10) 8 times Square = 218,340,105,584,896, which 218 trillion
But adjacent cannot have two or more of the same as {a1b2cc90, this character appears two times CC}
Can such data be generated in PHP?
If generating a single text data should be less likely to be cut into many parts ...

Reply to discussion (solution)

What does that mean?

$d = Str_split (' ABCD ');p Rint_r (Array_map (' Join ', F (4, $d))), function f ($n, $d) {  $t = Array_chunk ($d, 1);  if ($n > 2) $t = f ($n-1, $d);  foreach ($t as $x)    foreach (Array_chunk ($d, 1) as $y) {      if (end ($x)! = End ($y)) $r [] = Array_merge ($x, $y);    }  return $r;}

Array ([0] = abab [1] = ABAC [2] = Abad [3] = = ABCA [4] = = ABCB [5] [= ABCD] [6]    = ABDA [7] = ABDB [8] = ABDC [9] = = Acab [ten] = ACAC [one] = Acad [] = ACBA [19] = ACBC [] = ACBD [[+]] = ACDA [+] = acdb [+] = ACDC [[+]] = = Adab -ADAC [+] = Adad [+] = ADBA [] = ADBC [] = adbd [] = ADCA [+] = AD CB [3] = ADCD [+] = Baba [] = babc [] = babd [+] = Baca [[+] = + BACB  2] = [BACD] = bada [] [+] = badb [+] = BADC [+] = Bcab [Panax Notoginseng] = BCAC [+] =    BCAD [+] = BCBA [+] = BCBC [All] [] = BCBD [[] = BCDA [] = bcdb [] = BCDC [Bdab] = [[]] = BDAC [+] = Bdad [[] = BDBA [in] = BDBC [[] = BDBD [51] =& Gt BDCA [~] = bDCB [+] = BDCD [si] = caba [+] = CABC [[+] = cabd [] = caca [+] = CACB [ [+] = CACD [] = Cada [All] = cadb [+] = CADC [+] = Cbab [+] = Cbac [] =&gt ;    Cbad [[+] = CBCA [[+] = CBCB [] [] = CBCD [] = Cbda [] = CBDB [[]] = CBDC [Cdab] = [[] = [] = CDAC [All] = Cdad [] [] = cdba [] = CDBC [All] = CDBD [+] =&G T    CDCA [[+] = CDCB [] = CDCD [Bayi] = Daba [[+] = DABC [the] [] = DABD [+] = DACA [DACB] = [[+]] = DACD [[+]] = Dada [+] = DADB [[]] = DADC [All] = Dbab [] =&G T    Dbac [[] = Dbad [[]] = DBCA [94] = DBCB [up] = DBCD [] [] = Dbda [] = Dbdb [98] = DBDC [[+]] = Dcab [[+] = DCAC [101] = Dcad [102] = DCBA [103] = DCBC [104    ] = DCBD[DCDA] = [106] = dcdb [107] = DCDC) 

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