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A336803 Numbers k such that A230319(k) - A230319(k-1) = 2. 1
3, 6, 9, 12, 15, 19, 22, 26, 30, 34, 38, 43, 47, 51, 56, 60, 65, 70, 75, 79, 84, 89, 94, 99, 104, 110, 115, 120, 125, 130, 136, 141, 147, 152, 158, 163, 169, 174, 180, 185, 191, 197, 202, 208, 214, 220, 225, 231, 237, 243, 249, 255, 261, 267, 273, 279, 285, 291 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Sánchez Garza and Treviño proved the counting function for this sequence is asymptotic to x/log x. See link.

LINKS

Table of n, a(n) for n=1..58.

M. Sánchez Garza and E. Treviño, On a sequence related to the factoradic representation of an integer, Journal of Integer Sequences Vol. 24 (2021), Article 21.8.5.

EXAMPLE

3 is a term because A230319(3) - A230319(2) = 2.

MATHEMATICA

j[r_] := j[r] = Module[{k = 1}, While[k! <= k^(r - 1), k++]; k];

jPrimes = {}; Do[If[j[r + 1] - j[r] == 2, AppendTo[jPrimes, r], 0], {r, 1, 2500}]

PROG

(PARI) f(n) = my(k=1); while (k^n >= k!, k++); k; \\ A230319

isok(n) = f(n) - f(n-1) == 2; \\ Michel Marcus, Jan 27 2021

CROSSREFS

Cf. A230319.

Sequence in context: A083354 A156242 A060293 * A220657 A194273 A123581

Adjacent sequences:  A336800 A336801 A336802 * A336804 A336805 A336806

KEYWORD

nonn

AUTHOR

Enrique Treviño, Jan 27 2021

STATUS

approved

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Last modified October 20 01:40 EDT 2021. Contains 348099 sequences. (Running on oeis4.)