A097636 Odd composites of the form A024675(k) or 1+A024675(k), any k.

9, 15, 21, 27, 35, 39, 45, 51, 57, 65, 69, 77, 81, 87, 93, 99, 105, 111, 121, 129, 135, 145, 155, 161, 165, 171, 177, 187, 195, 205, 217, 225, 231, 237, 247, 255, 261, 267, 275, 279, 289, 301, 309, 315, 325, 335, 343, 351, 357, 363, 371, 377, 381, 387, 393, 399

Offset

1,1

Comments

Start from an auxiliary sequence of interprimes, incremented by 1 if even: 5, 7, 9, 13, 15, 19, 21, 27, 31,... Removing the primes from this auxiliary sequence of odd numbers yields the current sequence.

Links

Table of n, a(n) for n=1..56.

Mathematica

digits=200 (* find odd numbers between the primes nearest the average*) a=Table[If[(Mod[(Prime[n+1]+Prime[n])/2, 2]==1)&&( PrimeQ[(Prime[n+1]+Prime[n])/2]==False)&&( PrimeQ[(Prime[n+1]+Prime[n])/2+1]==False), (Prime[n+1]+Prime[n])/2, (Prime[n+1]+Prime[n])/2+1], {n, 2, digits}] b=Table[Prime[n], {n, 1, digits}] (* eliminate the primes from the sequence *) aa=Complement[a, b]

Crossrefs

Sequence in context: A172181 A063139 A163170 * A179384 A225513 A331662

Adjacent sequences: A097633 A097634 A097635 * A097637 A097638 A097639

Keyword

nonn,easy,less

Author

Roger L. Bagula, Sep 20 2004

Extensions

Definition clarified by the Assoc. Eds. of the OEIS, Jul 13 2010

Status

approved