A364037 - OEIS

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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.

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

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OFFSET

2,1

COMMENTS

All terms are squarefree. - Jon E. Schoenfield, Jul 02 2023

LINKS

Table of n, a(n) for n=2..61.

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

Adjacent sequences: A364034 A364035 A364036 * A364038 A364039 A364040

KEYWORD

nonn

AUTHOR

Jean-Marc Rebert, Jul 02 2023

STATUS

approved