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The prime digits in the sequence appear in blocks and the successive sizes of these blocks are given by the sequence itself.
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%I #7 Mar 23 2017 14:36:10

%S 1,2,4,3,5,6,7,22,20,8,9,10,11,12,23,13,25,27,14,15,32,33,21,16,17,35,

%T 37,52,18,19,40,41,42,53,55,57,72,73,75,77,222,223,24,43,225,227,232,

%U 233,235,237,26,44,45,252,253,28,46,47,255,257,220,48,49,60,61,62,272,273,275,63,277,322,323,29,64,65,325,327,332,221,66

%N The prime digits in the sequence appear in blocks and the successive sizes of these blocks are given by the sequence itself.

%C The sequence is started with a(1)=1 and always extended with the smallest integer not yet present that does not lead to a contradiction.

%e The blocks of prime digits are indicated hereunder by parentheses; the successive block-sizes are 1, 2, 4, 3, 5, 6,... which reproduces the sequence itself:

%e 1,(2),4,(3,5),6,(7,22,2)0,8,9,10,11,1(2,23),1(3,25,27),14,1(5,32,33,2)1,16,...

%Y The equivalent sequence dealing with nonprime digits is A275659.

%K nonn,base

%O 1,2

%A _Eric Angelini_ and _Lars Blomberg_, Aug 04 2016