[seqfan] a(n) concatenated to the leftmost digit of a(n+1) = prime

Eric Angelini Eric.Angelini at kntv.be
Tue Oct 28 17:07:56 CET 2014


Hello SeqFans,
a(n) concatenated to the leftmost digit of a(n+1) forms a prime.
S is extended with the smallest available integer not yet in S
and not halting immediately S. 
[Integers halting S are https://oeis.org/A032352].

S = 1,3,7,9,70,10,11,30,71,90,72,72,31,12,74,33,...

The last integer (33) extends S because 32 halts it.

Best,
É.







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