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a(n) cannot be prefixed or followed by any digit to form a prime ('empty' prefixes and suffixes are allowed).
0

%I #10 Aug 13 2024 14:36:10

%S 14612,27971,33170,36186,39608,40078,41165,41528,47382,55553,60806,

%T 62318,63056,65970,66818,70558,83986,86145,89072,89280,91538,93160,

%U 96222,97908,101532,102852,104609,105275,108312,108615,108792,109934

%N a(n) cannot be prefixed or followed by any digit to form a prime ('empty' prefixes and suffixes are allowed).

%C a(n) itself cannot be a prime to start with.

%e 104609 prefixed or followed by a digit from ('',1,2,3,4,5,6,7,8,9) never yields a prime: '_'104609'_' = 73 x 1433; '8'104609'3' = 3089 x 26237.

%Y Cf. A032682-A032685 and A032702-A032733.

%K nonn,base

%O 1,1

%A _Patrick De Geest_, May 15 1998

%E Offset changed by _Andrew Howroyd_, Aug 13 2024