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A077652 Primes whose initial and terminal decimal digits are identical. 3

%I #33 Mar 01 2023 06:41:03

%S 2,3,5,7,11,101,131,151,181,191,313,353,373,383,727,757,787,797,919,

%T 929,1021,1031,1051,1061,1091,1151,1171,1181,1201,1231,1291,1301,1321,

%U 1361,1381,1451,1471,1481,1511,1531,1571,1601,1621,1721,1741,1801,1811

%N Primes whose initial and terminal decimal digits are identical.

%C 1021 is the smallest of these not to be palindromic. - _Jonathan Vos Post_, Nov 02 2013

%C All palindromic primes (A002385) except 11 have an odd number of digits, therefore all terms > 11 with an even number of digits are non-palindromic in this sequence. - _M. F. Hasler_, Nov 02 2013

%H Bruno Berselli, <a href="/A077652/b077652.txt">Table of n, a(n) for n = 1..1000</a>

%t Do[s1=First[IntegerDigits[Prime[n]]]; s2=Last[IntegerDigits[Prime[n]]]; If[Equal[s1, s2], Print[Prime[n]]], {n, 1, 1000}]

%t itdQ[n_]:=Module[{idn=IntegerDigits[n]},idn[[1]]==idn[[-1]]]; Select[Prime[ Range[ 500]], itdQ] (* _Harvey P. Dale_, Apr 12 2013 *)

%o (Magma) [ p: p in PrimesUpTo(2000) | P[#P] eq P[1] where P is Intseq(p) ]; // Bruno Berselli, Jul 26 2011

%o (PARI) is(n)=digits(n)[1]==n%10&&isprime(n) \\ _M. F. Hasler_, Nov 02 2013

%Y Cf. A000030, A000040, A227858.

%K base,nonn

%O 1,1

%A _Labos Elemer_, Nov 19 2002

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Last modified April 16 17:08 EDT 2024. Contains 371749 sequences. (Running on oeis4.)