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A350233
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Integers that are divisible by 5 and not by 4, and whose reverse is divisible by 4 and not by 5.
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1
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25, 65, 210, 215, 230, 235, 250, 255, 270, 275, 290, 295, 405, 425, 445, 465, 485, 610, 615, 630, 635, 650, 655, 670, 675, 690, 695, 805, 825, 845, 865, 885, 2105, 2110, 2115, 2125, 2130, 2135, 2145, 2150, 2155, 2165, 2170, 2175, 2185, 2190, 2195, 2305, 2310, 2315, 2325, 2330, 2335
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OFFSET
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1,1
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COMMENTS
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Numbers beginning with 21, 23, 25, 27, 29, 40, 42, 44, 46, 48, 61, 63, 65, 67, 69, 80, 82, 84, 86, 88 and ending with 05, 10, 15, 25, 30, 35, 45, 50, 55, 65, 70, 75, 85, 90, 95. The number of d-digit terms is 3*10^(d-2) for d >= 3. - Jianing Song, Dec 24 2021
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LINKS
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EXAMPLE
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25 is term since it is divisible by 5 and not by 4, while 52, it reverse, is divisible by 4 and not by 5.
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MATHEMATICA
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Select[5 * Range[500], ! Divisible[#, 4] && Divisible[(r = IntegerReverse[#]), 4] && ! Divisible[r, 5] &] (* Amiram Eldar, Dec 21 2021 *)
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PROG
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(PARI) isok(k) = if ((k%4) && !(k%5), k=fromdigits(Vecrev(digits(k))); (k%5) && !(k%4));
(Python)
from itertools import count, islice
def A350233gen(): return filter(lambda n:(m := int(str(n)[::-1])) % 5 and not m % 4, filter(lambda n: n % 4 and not n % 5, count(1)))
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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