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A062352 Palindromic primes with strictly decreasing digits up to the middle and then strictly increasing. 6

%I #14 Aug 04 2022 15:04:30

%S 2,3,5,7,11,101,313,727,757,919,929,31013,73037,73237,74047,76367,

%T 91019,93139,93239,94049,94349,96269,96469,97379,97579,98389,98689,

%U 7310137,7521257,7540457,7630367,7632367,7654567,9320239,9610169

%N Palindromic primes with strictly decreasing digits up to the middle and then strictly increasing.

%C The last term of this finite series is 97654321012345679.

%C There are 84 terms. - _Michael S. Branicky_, Aug 04 2022

%H Michael S. Branicky, <a href="/A062352/b062352.txt">Table of n, a(n) for n = 1..84</a> (full sequence)

%H Patrick De Geest, <a href="http://www.worldofnumbers.com/palpri.htm">World of Palindromic Primes</a>

%e 31013 belongs to the sequence as it is a palindromic prime in which the digits are decreasing up to the middle digit 0 and then increasing.

%o (Python)

%o from sympy import isprime

%o from itertools import combinations

%o def bgen():

%o for digits in range(1, 20):

%o for left in combinations("9876543210", (digits+1)//2):

%o left = "".join(left)

%o yield int(left + (left[:digits//2])[::-1])

%o afull = sorted(filter(isprime, bgen()))

%o print(afull) # _Michael S. Branicky_, Aug 04 2022

%Y Cf. A062351.

%K nonn,base,fini,full

%O 1,1

%A _Amarnath Murthy_, Jun 23 2001

%E Corrected and edited by _Patrick De Geest_, Jun 07 2003

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Last modified July 13 18:16 EDT 2024. Contains 374285 sequences. (Running on oeis4.)