Shyam Sunder Gupta sent a follow-up to Puzzle 1242, ands wrote on Oct 27, 2025:

I have investigated the puzzle for cube and reverse also, and the smallest examples of "3, 4 & 5 primes" are given below:

a) p1 = 5 -> p2 = 521 -> p3 = 167024141.

b) p1 = 41243 -> p2 = 70957362735107 ->
p3 = 340072580562292758983063684559587385662753 ->
p4 = 7771387902509461541804448596476171134994618019090021926170209536132534500779209350826609131671267667238
6860916228621367192393.

c) p1 = 11217940001 -> p2 = 1000283544657170636980000961141 ->
p3 = 1226272077252711947390945706425645203529615506075666763701999365951325413406207815780580001 ->
p4 = 100047145658058318593979730778331416039914635950352433760665777316716445290784151466967668560587748
58791100911195180044557430738541444309411451294908378744129380397940195260370815724270212201975137786307
12147757747734834125822621875520756184650146211676326793566038993481 ->
p5 = 1463076912982113627169683307080233968332127412643952920249551233336733
1928669243078600367519260936882087066057019084414786667360450552531102
6081347929012558226140017088148937551854618601902651614078540153622170
6213657192423941122453492805695549493243620499604092396589818815221817
7814890671161471144188095822226502922208208905055663189003969729095745
5612603465881188740134621847102430336606238321144136009146389850335826
7546255986917267500754051361228583361414916791605644052837437603579803
5268679980869767413162546732983830799588112788151085444905524028392571
5169422118668970115545627398078512018026643746076332660725094433713248
6488471224604338146738998046511392083753555523673776157338892124890668
9330258719799373856933517345329609746706346745930366613853277344889173
30603904919080346456293592640666305141001.   

Q. Send your largest sequence of primes for this procedure.