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A356171
Odd numbers that are not divisible by two consecutive prime numbers.
5
1, 3, 5, 7, 9, 11, 13, 17, 19, 21, 23, 25, 27, 29, 31, 33, 37, 39, 41, 43, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 137, 139, 141, 145, 147, 149, 151, 153, 155, 157, 159, 161, 163
OFFSET
1,2
COMMENTS
Numbers k such that k and the smallest positive x such that k divides x*A003961(x) are coprime, where A003961 is fully multiplicative with a(p) = nextprime(p).
PROG
(PARI)
A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
A356172(n) = for(k=1, oo, if((k*A003961(k))%n==0, return(1==gcd(n, k))));
isA356171(n) = A356172(n);
CROSSREFS
Odd terms in A319630.
Positions of 1's in A356166, positions of 0's in A356169.
Cf. A003961, A356164, A356172 (characteristic function).
Sequence in context: A324846 A324760 A324761 * A244579 A151991 A360114
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 28 2022
STATUS
approved