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Primes with odd largest digit.
2

%I #17 Jun 20 2023 15:52:29

%S 3,5,7,11,13,17,19,23,29,31,37,47,53,59,67,71,73,79,89,97,101,103,107,

%T 109,113,127,131,137,139,149,151,157,167,173,179,191,193,197,199,223,

%U 227,229,233,239,251,257,269,271,277,293,307,311,313,317,331,337,347

%N Primes with odd largest digit.

%H Harvey P. Dale, <a href="/A155058/b155058.txt">Table of n, a(n) for n = 1..2000</a>

%e 181 is prime but has 8 as its largest digit, so 181 is not a term.

%e 191 is prime and has 9 as its largest digit, so 191 is a term.

%t Select[Prime[Range[100]],OddQ[Max[IntegerDigits[#]]]&] (* _Harvey P. Dale_, Jun 20 2023 *)

%o (PARI) isok(p) = isprime(p) && (vecmax(digits(p)) % 2); \\ _Michel Marcus_, Feb 18 2021

%Y Cf. A000040, A154767.

%K nonn,base,less

%O 1,1

%A _Juri-Stepan Gerasimov_, Jan 19 2009

%E 181 replaced with 191 by _Ray Chandler_, Jan 31 2009