A164275 The absolute value of (the n-th isolated composite minus the n-th isolated prime).

2, 17, 25, 29, 23, 25, 19, 11, 13, 11, 25, 23, 49, 35, 35, 61, 67, 59, 59, 79, 97, 163, 169, 185, 229, 263, 283, 287, 305, 307, 451, 455, 455, 479, 499, 631, 635, 649, 653, 653, 709, 781, 821, 823, 823, 833, 937, 953, 979, 979, 1067, 1073, 1111, 1135, 1145, 1201, 1279

Offset

1,1

Comments

An isolated composite is surrounded by two primes, and therefore an average of a twin prime pair.

Links

Table of n, a(n) for n=1..57.

Formula

a(n)= |A014574(n)-A007510(n)|.

Example

a(1)=abs(4-2)=2, a(2)=abs(6-23)=17.

Crossrefs

Cf. A007510, A014574.

Sequence in context: A107137 A086322 A340048 * A284646 A270344 A300134

Adjacent sequences: A164272 A164273 A164274 * A164276 A164277 A164278

Keyword

nonn

Author

Juri-Stepan Gerasimov, Aug 11 2009

Extensions

Entries checked by R. J. Mathar, Aug 27 2009

Status

approved