A156657 - OEIS

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A156657

Numbers that are not safe primes.

0, 1, 2, 3, 4, 6, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

COMMENTS

A156659(a(n)) = 0; complement of A005385; A059456 is a subsequence;

A010051(a(n))*A010051((a(n)-1)/2) = 0.

LINKS

Table of n, a(n) for n=1..72.

CROSSREFS

Sequence in context: A254077 A377078 A352968 * A026431 A026433 A354148

Adjacent sequences: A156654 A156655 A156656 * A156658 A156659 A156660

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Feb 13 2009

STATUS

approved