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A329876 Lexicographically earliest sequence of positive integers such that for n > 1, the concatenation of a(n), a(n-1), ..., a(1), in decimal, is a prime number.

%I A329876 #10 Nov 23 2019 13:59:12
%S A329876 1,1,2,4,3,2,4,15,3,9,20,4,3,11,31,6,24,23,82,11,21,3,22,20,63,19,56,
%T A329876 22,17,42,105,31,2,4,27,96,42,5,72,19,20,22,32,102,31,104,4,24,95,21,
%U A329876 13,12,9,38,3,58,38,78,31,119,31,45,107,42,12,9,21,66,181
%N A329876 Lexicographically earliest sequence of positive integers such that for n > 1, the concatenation of a(n), a(n-1), ..., a(1), in decimal, is a prime number.
%C A329876 For any n > 0, the concatenation of a(n+1) and A053582(n) gives A053582(n+1).
%H A329876 Rémy Sigrist, <a href="/A329876/b329876.txt">Table of n, a(n) for n = 1..501</a>
%F A329876 The first terms, alongside their concatenations, are:
%F A329876   n   a(n)  A053582(n)
%F A329876   --  ----  -----------
%F A329876    1     1            1
%F A329876    2     1           11
%F A329876    3     2          211
%F A329876    4     4         4211
%F A329876    5     3        34211
%F A329876    6     2       234211
%F A329876    7     4      4234211
%F A329876    8    15    154234211
%F A329876    9     3   3154234211
%F A329876   10     9  93154234211
%o A329876 (PARI) print1 (v=1); for (n=2, 69, s=(b=10)^#digits(v,b); for (k=1, oo, if (isprime(v+=s), print1 (", "k); break)))
%Y A329876 See A053582 for the corresponding concatenations.
%K A329876 nonn,base
%O A329876 1,3
%A A329876 _Rémy Sigrist_, Nov 23 2019