A350441
Numbers m such that 4^m reversed is prime.
Original entry on oeis.org
2, 5, 12, 35, 75, 182, 828, 1002, 1063, 2168, 6345, 6920, 10054, 14444, 51465
Offset: 1
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Select[Range[2200], PrimeQ[IntegerReverse[4^#]] &] (* Amiram Eldar, Dec 31 2021 *)
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isok(m) = isprime(fromdigits(Vecrev(digits(4^m))))
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from sympy import isprime
m = 4
for n in range (1, 2000):
if isprime(int(str(m)[::-1])):
print(n)
m *= 4
A071586
Powers of 8 written backwards.
Original entry on oeis.org
1, 8, 46, 215, 6904, 86723, 441262, 2517902, 61277761, 827712431, 4281473701, 2954399858, 63767491786, 888318557945, 4011156408934, 23888027348153, 656017679474182, 8425863189971522, 48918490589341081, 278558570881511441
Offset: 0
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for(i=1,50,n=8^i; s=ceil(log(n)/log(10)); print1(sum(i=0,s,10^(s-i-1)*(floor(n/10^i)-10*floor(n/10^(i+1)))),","))
A071588
Powers of 6 written backwards.
Original entry on oeis.org
1, 6, 63, 612, 6921, 6777, 65664, 639972, 6169761, 69677001, 67166406, 650797263, 6332876712, 61049606031, 69046146387, 675489481074, 6547099011282, 63744495662961, 614866659955101, 694010047953906, 6792600448516563
Offset: 0
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FromDigits[Reverse[IntegerDigits[#]]]&/@(6^Range[0,30]) (* Harvey P. Dale, Feb 02 2012 *)
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for(i=1,50,n=5^i; s=ceil(log(n)/log(10)); print1(sum(i=0,s,10^(s-i-1)*(floor(n/10^i)-10*floor(n/10^(i+1)))),","))
Showing 1-3 of 3 results.
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