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 A084837 Palindromic primes with nonincreasing digits up to the middle and then nondecreasing. 2

%I #11 Jun 27 2022 01:52:53

%S 2,3,5,7,11,101,313,727,757,919,929,31013,72227,73037,73237,74047,

%T 75557,76367,76667,77377,77477,91019,93139,93239,94049,94349,96269,

%U 96469,97379,97579,98389,98689,3211123,3222223,3310133,3321233,3331333,7100017,7300037,7310137

%N Palindromic primes with nonincreasing digits up to the middle and then nondecreasing.

%H Michael S. Branicky, <a href="/A084837/b084837.txt">Table of n, a(n) for n = 1..10000</a>

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

%o (Python)

%o from sympy import isprime

%o from itertools import count, islice, combinations_with_replacement as mc

%o def agen(): # generator of terms

%o yield from (2, 3, 5, 7, 11)

%o for d in count(2):

%o nind = (int("".join(m+m[:-1][::-1])) for m in mc("9876543210", d))

%o yield from sorted(filter(isprime, nind))

%o print(list(islice(agen(), 40))) # _Michael S. Branicky_, Jun 26 2022

%Y Cf. A084836, A062351, A062352.

%K nonn,base

%O 1,1

%A _Patrick De Geest_, Jun 07 2003

%E a(38) and beyond from _Michael S. Branicky_, Jun 26 2022

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