A163602 First differences of A161753.
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
Offset: 1
Examples
a(1)=1=1^2-0^2. a(2)=15=4^2-1^2. a(3)=20=6^2-4^2.
Links
- G. C. Greubel, Table of n, a(n) for n = 1..5000
Programs
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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
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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 *)
Extensions
a(6) corrected by R. J. Mathar, Aug 07 2009
Comments