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A344549 Largest prime with strictly ascending consecutive digits in base n. 1

%I #13 Jun 14 2021 15:46:31

%S 5,11,19,569,41,2423,207593,23456789,811,160403,95401,235776949,

%T 208888661909,9927935178558959,889872307619,14707209648376466477,

%U 1245691,340387811,96209320840499118292907,9614505639105223858867,1068038871569,28923381229,202821360694037,409991957243270502360389

%N Largest prime with strictly ascending consecutive digits in base n.

%C This sequence in ascending bases, starting with base 3: 12, 23, 34, 2345, 56, 4567, 345678, 23456789, 678, 789AB, 34567, 23456789, 56789ABCDE, 23456789ABCDEF, 789ABCDEFG, 23456789ABCDEFGH, 9ABCD, 56789AB, 3456789ABCDEFGHIJK, 3456789ABCDEFGHIJ, DEFGHIJKL, 6789ABCD, 23456789ABC, 9ABCDEFGHIJKLMNOP.

%e 12_3 = 5 is the largest prime number with strictly ascending digits for this base.

%o (PARI) a(n)={forstep(k=n-1, 1, -1, forstep(j=n-k, 1, -1, my(t=fromdigits([j..j+k-1], n)); if(isprime(t), return(t)))); oo} \\ _Andrew Howroyd_, May 22 2021

%Y Cf. A006055, A138141.

%K nonn,base

%O 3,1

%A _Hervé Loiseau_, May 22 2021

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Last modified August 25 12:12 EDT 2024. Contains 375439 sequences. (Running on oeis4.)