cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A350441 Numbers m such that 4^m reversed is prime.

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%I A350441 #26 Feb 06 2022 23:08:11
%S A350441 2,5,12,35,75,182,828,1002,1063,2168,6345,6920,10054,14444,51465
%N A350441 Numbers m such that 4^m reversed is prime.
%C A350441 From _Bernard Schott_, Jan 30 2022: (Start)
%C A350441 If m is a term, then u = 2*m is a term of A057708, because 4^m = 2^(2*m). In fact, terms of this sequence here are half the even terms of A057708.
%C A350441 If m is a term that is multiple of 3, then k = 2*m/3 is a term of A350442, because 4^m = 8^(2m/3). First examples: m = 12, 75, 828, 1002, 6345, 51465, ... and corresponding k = 8, 50, 552, 668, 4230, 34310, ... (End)
%t A350441 Select[Range[2200], PrimeQ[IntegerReverse[4^#]] &] (* _Amiram Eldar_, Dec 31 2021 *)
%o A350441 (PARI) isok(m) = isprime(fromdigits(Vecrev(digits(4^m))))
%o A350441 (Python)
%o A350441 from sympy import isprime
%o A350441 m = 4
%o A350441 for n in range (1, 2000):
%o A350441     if isprime(int(str(m)[::-1])):
%o A350441         print(n)
%o A350441     m *= 4
%Y A350441 Cf. A058996, A071582.
%Y A350441 Cf. Numbers m such that k^m reversed is prime: A057708 (k=2), this sequence (k=4), A058993 (k=5), A058994 (k=7), A350442 (k=8), A058995 (k=13).
%K A350441 nonn,base,more
%O A350441 1,1
%A A350441 _Mohammed Yaseen_, Dec 31 2021
%E A350441 a(11)-a(15) from _Amiram Eldar_, Dec 31 2021