A036341 Concatenation of prime p and nextprime(p) is prime -> cycles of 4 steps possible.

127787377, 1510818931, 3147482977, 3307903909, 3621408103, 3964636549, 7224979183, 7881628361, 8043354509, 8740618759, 10091655397, 10164789521, 10194261067, 10380609119, 10436432219, 11472028801, 12059694769, 13887362681, 14880879703, 15197340049

Offset: 1

Author

Patrick De Geest, Dec 15 1998

Keywords

• nonn
• base

Comments

a(1)-a(5) found by Jo Yeong Uk (hyukjo(AT)sigma.chungnam.ac.kr).

Links

• Giovanni Resta, Table of n, a(n) for n = 1..4000
• Carlos Rivera, Puzzle 29. P_i = P_(i-1) & nxtprm(P_(i-1)), P_i = prime for i => 1, The Prime Puzzles and Problems Connection.

Crossrefs

Cf. A030459, A034593, A036339, A036340.

Extensions

Offset corrected and terms a(6) and beyond added by Giovanni Resta, May 14 2020