A163646 Two copies of the twin primes inserted at positions depending on prime(n) being isolated or not.

3, 3, 5, 7, 11, 13, 17, 19, 5, 29, 31, 7, 41, 43, 11, 13, 59, 61, 17, 71, 73, 19, 29, 31, 41, 101, 103, 107, 109, 43, 59, 61, 137, 139, 149, 151, 71, 73, 101, 103, 179, 181, 191, 193, 197, 199, 107, 109, 227, 229, 137, 239, 241, 139, 149, 151, 269, 271, 179, 281, 283, 181, 191

Offset

1,1

Comments

The indices n of this sequence are labeled individually by 0 or 1 depending on whether prime(n) is in the list of isolated primes (A007510) or in the list of twin primes (A001097), which yields 0,1,1,1,1,1,1,1,0,1,1,0,....

The sequence is defined by placing one copy of the twin prime sequence A001097 at the positions labeled 0, and a second copy of the twin prime sequence at the positions labeled 1.

Links

Table of n, a(n) for n=1..63.

Crossrefs

Cf. A000040, A001097, A007510.

Sequence in context: A176347 A161834 A141867 * A323529 A328222 A306276

Adjacent sequences: A163643 A163644 A163645 * A163647 A163648 A163649

Keyword

nonn,easy,less

Author

Juri-Stepan Gerasimov, Aug 02 2009

Extensions

Definition clarified, entries checked by R. J. Mathar, Aug 12 2009

Typos in comment on labeling corrected by R. J. Mathar, Aug 29 2009

Status

approved