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A358673
Numbers k such that for all factorizations of k as x*y, the sum (x * y') + (x' * y) is carryfree when the addition is done in the primorial base, A049345. Here n' stands for A003415(n), the arithmetic derivative of n.
4
1, 2, 3, 4, 5, 6, 7, 11, 12, 13, 14, 17, 18, 19, 23, 26, 27, 29, 31, 37, 38, 41, 43, 47, 53, 59, 61, 62, 63, 67, 70, 71, 73, 74, 79, 83, 86, 89, 97, 99, 101, 103, 107, 109, 113, 117, 122, 127, 131, 134, 137, 139, 146, 149, 151, 153, 154, 157, 158, 163, 167, 173, 179, 181, 186, 190, 191, 193, 194, 195
OFFSET
1,2
COMMENTS
Numbers k such that there are no factorization of k into such a pair of natural numbers x and y, that the sum (x * A003415(y)) + (A003415(x) * y) would generate any carries when the addition is done in the primorial base.
FORMULA
{k | A358235(k) = A038548(k)}.
EXAMPLE
Refer to the examples in A358235 to see why 6 and 63 are terms of this sequence, while 24 is not.
PROG
(PARI) isA358673(n) = A358672(n);
CROSSREFS
Cf. A000040 (subsequence), A003415, A049345, A358235, A358672 (characteristic function), A358674 (complement).
Cf. also A358671.
Sequence in context: A275910 A032971 A099466 * A032976 A174219 A115037
KEYWORD
nonn,base
AUTHOR
Antti Karttunen, Nov 26 2022
STATUS
approved