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A163602 First differences of A161753. 1
1, 15, 20, 28, 17, 19, 44, 52, 29, 31, 68, 76, 41, 43, 92, 49, 51, 53, 55, 116, 124, 65, 67, 69, 71, 148, 77, 79, 164, 172, 89, 91, 188, 97, 99, 101, 103, 212, 109, 111, 113, 115, 236, 244, 125, 127, 129, 131, 268, 137, 139, 284, 292, 149, 151, 153, 155, 316, 161, 163, 332 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..5000

FORMULA

a(n) = A161753(n+1) - A161753(n).

EXAMPLE

a(1)=1=1^2-0^2. a(2)=15=4^2-1^2. a(3)=20=6^2-4^2.

MAPLE

A141468 := proc(n) if n <= 2 then n-1 ; else for a from procname(n-1)+1 do if not isprime(a) then RETURN(a) ; fi; od: fi; end;

A161753 := proc(n) A141468(n)^2 ; end:

A163602 := proc(n) A161753(n+1)-A161753(n) ; end: seq(A163602(n), n=1..100) ; # R. J. Mathar, Aug 07 2009

MATHEMATICA

A161753 := With[{nn = 500}, Complement[Range[0, nn], Prime[Range[PrimePi[nn]]]]^2]; Table[A161753[[n + 1]] - A161753[[n]], {n, 1, 50}] (* G. C. Greubel, Jul 29 2017 *)

Differences[With[{nn=100}, Complement[Range[0, nn], Prime[Range[ PrimePi[ nn]]]]^2]] (* Harvey P. Dale, Mar 03 2020 *)

CROSSREFS

Cf. A001248, A141468, A161753.

Sequence in context: A143321 A066860 A120159 * A074236 A086770 A111200

Adjacent sequences:  A163599 A163600 A163601 * A163603 A163604 A163605

KEYWORD

nonn,easy

AUTHOR

Juri-Stepan Gerasimov, Aug 01 2009

EXTENSIONS

a(6) corrected by R. J. Mathar, Aug 07 2009

STATUS

approved

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Last modified July 5 23:36 EDT 2020. Contains 335475 sequences. (Running on oeis4.)