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A111057 Minimal set in the sense of A071062 of prime-strings in base 12 for primes of the form 4n+1. 0

%I

%S 5,13,37,73,97,109,313,337,373,409,421,577,601,661,709,1009,1033,1093,

%T 1129,1489,1609,1669,3457,7537,12721,13729,17401,17569,19009,19141,

%U 20593,20641,165877,208501,221173,225781,226201,226357,228793,246817,246937,248821,1097113,2695813,2735269,2736997,2737129,32555521,388177921

%N Minimal set in the sense of A071062 of prime-strings in base 12 for primes of the form 4n+1.

%C Maple worksheet available upon request. Here is the minimal set of primes of the form 4n+1 in base 12, where X is ten and E is eleven. 5, 11, 31, 61, 81, 91, 221, 241, 271, 2X1, 2E1, 401, 421, 471, 4E1, 701, 721, 771, 7X1, X41, E21, E71, 2001, 4441, 7441, 7E41, X0X1, X201, E001, E0E1, EE01, EE41, 7EEE1, X07E1, X7EE1, XX7E1, XXXX1, XXEE1, E04X1, EXX01, EXXX1, EEEE1, 44XXX1, XX00E1, XEXXE1, XEEXE1, XEEEX1, XXX0001, XX000001. Note that the last prime in the set is the same as the last prime in the minimal set of all primes. See A110600. I am checking certain ranges past this last prime but flow-charting the possibilities leads me to believe I have found the full sequence. The minimal set of prime strings in base 12 for primes of the form 4n+3 is [3, 7, E] since every 4n+3 prime greater than 3 ends in either 7 or E.

%H J. Shallit, <a href="http://www.cs.uwaterloo.ca/~shallit/Papers/minimal5.ps">Minimal primes</a>, J. Recreational Mathematics, vol. 30.2, pp. 113-117, 1999-2000.

%e a(11)=421="2E1" since the pattern "*2*E*1*" does not occur in any previously found prime of the form 4n+1. Assuming all previous members of the list have been similarly recursively constructed, then "401" (577 in base 10) is the next prime in the list. The basic rule is: if no substring of p matches any previously found prime, add p to the list. The basic theorem of minimal sets says that this process will terminate, that is, the minimal set is always finite.

%Y Cf. A071062, A071070, A110600, A110615.

%K base,fini,full,nonn,uned

%O 1,1

%A _Walter Kehowski_, Oct 06 2005

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Last modified May 13 04:09 EDT 2021. Contains 343836 sequences. (Running on oeis4.)