A350442
Numbers m such that 8^m reversed is prime.
Original entry on oeis.org
8, 15, 50, 552, 668, 1011, 1163, 1215, 2199, 4230, 7231, 34310
Offset: 1
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Select[Range[2200], PrimeQ[IntegerReverse[8^#]] &] (* Amiram Eldar, Dec 31 2021 *)
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isok(m) = isprime(fromdigits(Vecrev(digits(8^m))))
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from sympy import isprime
m = 8
for n in range (1, 2000):
if isprime(int(str(m)[::-1])):
print(n)
m *= 8
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)))),","))
A134114
Powers of 8 written backwards and sorted.
Original entry on oeis.org
1, 8, 46, 215, 6904, 86723, 441262, 2517902, 61277761, 827712431, 2954399858, 4281473701, 63767491786, 888318557945, 4011156408934, 23888027348153, 656017679474182, 8425863189971522, 48918490589341081, 278558570881511441
Offset: 1
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rev:= proc(n) local L,i; L:= convert(n,base,10); add(L[-i]*10^(i-1),i=1..nops(L)) end proc:
sort(map(rev,[seq(8^i,i=0 .. floor(log[8](10^20)))])); # Robert Israel, Mar 05 2025
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IntegerReverse[8^Range[0,20]]//Sort (* Harvey P. Dale, Jul 19 2024 *)
Showing 1-3 of 3 results.
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