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A300959 Number of prime factors of the n-th Lucas-Carmichael number. 1
3, 3, 3, 3, 3, 3, 3, 4, 3, 4, 3, 3, 3, 4, 4, 3, 4, 3, 3, 3, 4, 3, 3, 4, 3, 3, 3, 4, 3, 4, 3, 3, 4, 4, 4, 3, 3, 4, 3, 4, 4, 3, 4, 3, 5, 4, 3, 3, 3, 3, 4, 3, 3, 4, 3, 4, 4, 3, 3, 3, 5, 4, 4, 3, 3, 4, 3, 4, 3, 3, 4, 4, 4, 3, 3, 4, 4, 3, 4, 4, 4, 4, 3, 5, 3, 4, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The number of prime factors is always >= 3.

LINKS

Tim Johannes Ohrtmann, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A001221(A006972(n)).

PROG

(PARI) islc(n)=my(f=factor(n)); for(i=1, #f[, 1], if((n+1)%(f[i, 1]+1) || f[i, 2]>1, return(0))); #f[, 1]>1; \\ from A006972

lista(nn) = for (n=1, nn, if (islc(n), print1(omega(n), ", "))); \\ Michel Marcus, Mar 17 2018

CROSSREFS

Cf. A006972 (Lucas-Carmichael numbers).

Cf. A216925, A216926, A216927, A217002, A217003, A217091 (Lucas-Carmichael numbers with 3 to 8 prime factors).

Cf. A216928 (Least Lucas-Carmichael number with n prime factors).

Sequence in context: A303168 A162844 A115787 * A259581 A105592 A210745

Adjacent sequences:  A300956 A300957 A300958 * A300960 A300961 A300962

KEYWORD

nonn

AUTHOR

Tim Johannes Ohrtmann, Mar 17 2018

STATUS

approved

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Last modified January 19 01:11 EST 2021. Contains 340262 sequences. (Running on oeis4.)