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A156542 Number of distinct Sophie Germain prime factors of n. 7
0, 1, 1, 1, 1, 2, 0, 1, 1, 2, 1, 2, 0, 1, 2, 1, 0, 2, 0, 2, 1, 2, 1, 2, 1, 1, 1, 1, 1, 3, 0, 1, 2, 1, 1, 2, 0, 1, 1, 2, 1, 2, 0, 2, 2, 2, 0, 2, 0, 2, 1, 1, 1, 2, 2, 1, 1, 2, 0, 3, 0, 1, 1, 1, 1, 3, 0, 1, 2, 2, 0, 2, 0, 1, 2, 1, 1, 2, 0, 2, 1, 2, 1, 2, 1, 1, 2, 2, 1, 3, 0, 2, 1, 1, 1, 2, 0, 1, 2, 2, 0, 2, 0, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

a(n) <= A001221(n));

a(A156541(n)) = A001221(A156541(n)); a(A156543(n)) = 0;

a(A005384(n)) = 1; a(A053176(n)) = 0.

LINKS

R. Zumkeller, Table of n, a(n) for n = 1..10000

CROSSREFS

Sequence in context: A025911 A060184 A055639 * A066360 A061358 A025866

Adjacent sequences:  A156539 A156540 A156541 * A156543 A156544 A156545

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Feb 10 2009

STATUS

approved

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Last modified December 11 10:48 EST 2018. Contains 318049 sequences. (Running on oeis4.)