A180108 Integers where the primes are split into two consecutive numbers.

0, 1, 2, 1, 2, 4, 2, 3, 6, 3, 4, 8, 9, 10, 5, 6, 12, 6, 7, 14, 15, 16, 8, 9, 18, 9, 10, 20, 21, 22, 11, 12, 24, 25, 26, 27, 28, 14, 15, 30, 15, 16, 32, 33, 34, 35, 36, 18, 19, 38, 39, 40, 20, 21, 42, 21, 22, 44, 45, 46, 23, 24, 48, 49, 50, 51, 52, 26, 27, 54, 55, 56, 57, 58, 29, 30

Offset

0,3

Comments

The even prime 2 is not split.

Links

Table of n, a(n) for n=0..75.

Example

The prime 29 is split into 14 and 15.

Mathematica

f[n_] := If[ !PrimeQ@ n || n == 2, n, {(n - 1)/2, (n + 1)/2}]; Array[ f, 60, 0] // Flatten (* Robert G. Wilson v, Aug 15 2010 *)

Crossrefs

Cf. A000040, A002808.

Sequence in context: A099470 A099254 A186731 * A300417 A121339 A307236

Adjacent sequences: A180105 A180106 A180107 * A180109 A180110 A180111

Keyword

base,nonn

Author

Parthasarathy Nambi, Aug 10 2010

Extensions

More terms from Robert G. Wilson v, Aug 15 2010

Status

approved