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A341845
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a(n) = A061026(2n): smallest k such that 2n divides phi(k), phi = A000010.
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1
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3, 5, 7, 15, 11, 13, 29, 17, 19, 25, 23, 35, 53, 29, 31, 51, 103, 37, 191, 41, 43, 69, 47, 65, 101, 53, 81, 87, 59, 61, 311, 85, 67, 137, 71, 73, 149, 229, 79, 123, 83, 129, 173, 89, 181, 141, 283, 97, 197, 101, 103, 159, 107, 109, 121, 113, 229, 177, 709, 143
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OFFSET
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1,1
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COMMENTS
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A061026(n) = A061026(2n) for odd n > 1 since phi(m) is even for m >= 3. In this sequence the redundant values are omitted.
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LINKS
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EXAMPLE
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a(12) = 35 since phi(35) = 24 is divisible by 2*12, and there is no m < 12 such that phi(m) is divisible by 2*12.
a(16) = 51 since phi(51) = 32 is divisible by 2*16, and there is no m < 16 such that phi(m) is divisible by 2*16.
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PROG
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(PARI) a(n) = for(m=1, (2*n)^2, if(eulerphi(m)%(2*n)==0, return(m)))
(Python)
from sympy import totient as phi
def a(n):
k = 1
while phi(k)%(2*n) != 0: k += 1
return k
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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