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A097636 Odd composites of the form A024675(k) or 1+A024675(k), any k. 0
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified August 4 13:04 EDT 2021. Contains 346447 sequences. (Running on oeis4.)