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A364037
Least number k such that the floor of the average of the distinct prime factors of k is n, or -1 if no such number exists.
3
2, 3, 14, 5, 22, 7, 39, 34, 38, 11, 46, 13, 115, 58, 62, 17, 155, 19, 111, 82, 86, 23, 94, 141, 235, 106, 159, 29, 118, 31, 183, 305, 134, 201, 142, 37, 219, 365, 158, 41, 166, 43, 415, 178, 267, 47, 623, 194, 291, 202, 206, 53, 214, 218, 327, 226, 339, 59, 791, 61
OFFSET
2,1
COMMENTS
All terms are squarefree. - Jon E. Schoenfield, Jul 02 2023
FORMULA
a(p) = p for prime p. - David A. Corneth, Jul 02 2023
EXAMPLE
a(4) = 14, because 14 = 2 * 7, floor((2 + 7) / 2) = 4, and no lesser number satisfies this.
MATHEMATICA
seq[len_, kmax_] := Module[{s = Table[0, {len}], c = 0, k = 2, i}, While[c < len && k < kmax, i = Floor[Mean[FactorInteger[k][[;; , 1]]]] - 1; If[i <= len && s[[i]] == 0, c++; s[[i]] = k]; k++]; s]; seq[60, 1000] (* Amiram Eldar, Jul 02 2023 *)
PROG
(PARI) f(n) = my(p = factor(n)[, 1]); vecsum(p)\#p; \\ A363895
a(n) = my(k=2); while (f(k) != n, k++); k; \\ Michel Marcus, Jul 02 2023
CROSSREFS
Cf. A363895.
Sequence in context: A288770 A249826 A352407 * A321226 A337329 A329365
KEYWORD
nonn
AUTHOR
Jean-Marc Rebert, Jul 02 2023
STATUS
approved