A143676 (0, 1, 2, 3, 2^2, 5, 2*3, 7, 2^3, 3^2, 2*5, 11, 2^2*3, 13,..) becomes (abs (0-1-2, 3-2-2, 5-2-3, 7-2-3, 3-2-2, 5-11-2, 2-3-13,..)).

3, 1, 0, 2, 1, 8, 14, 8, 1, 12, 19, 6, 6, 18, 4, 14, 1, 24, 33, 6, 8, 4, 3, 16, 12, 43, 8, 39, 6, 20, 41, 6, 5, 16, 64, 4, 8, 7, 12, 55, 63, 32, 7, 12, 12, 63, 9, 10, 66, 72, 38, 1, 24, 6, 68, 4, 39, 79, 9, 28, 28, 97, 3, 15, 23, 30, 23, 6, 88, 3, 7, 98, 18, 98, 5, 48, 103, 109, 14, 36, 116, 20

Offset

1,1

Links

Table of n, a(n) for n=1..82.

Example

Abs(0-1-2)=abs(-3)=3=a(1).
Abs(3-2-2)=abs(-1)=1=a(2).
Abs(5-2-3)=abs(0)=0=a(3).
Abs(7-2-3)=abs(2)=2=a(4).
Abs(3-2-2)=abs(-1)=1=a(5).
Abs(5-11-2)=abs(-8)=8 =a(6).
Abs(2-3-13)=abs(-14)=14=a(7), etc.

Maple

pflat2 := proc(nmax) local a, ifs, n, p, c ; a := [0, 1] ; for n from 2 to nmax do ifs := ifactors(n)[2] ; for p in ifs do a := [op(a), op(1, p)] ; if op(2, p) > 1 then a := [op(a), op(2, p)] ; fi; od: od: a ; end: pL := pflat2(300) : for n from 1 to nops(pL)-4 by 3 do printf("%d, ", abs(op(n, pL)-op(n+1, pL)-op(n+2, pL)) ) ; od: # R. J. Mathar, Nov 06 2008

Mathematica

Abs[#[[1]]-#[[2]]-#[[3]]]&/@Partition[Join[{0, 1}, Flatten[Table[ DeleteCases[ Flatten[FactorInteger[n]], 1], {n, 2, 120}]]], 3] (* Harvey P. Dale, Apr 02 2015 *)

Crossrefs

Cf. A141269, A141270.

Sequence in context: A101548 A117430 A354795 * A002726 A119734 A073200

Adjacent sequences: A143673 A143674 A143675 * A143677 A143678 A143679

Keyword

nonn

Author

Juri-Stepan Gerasimov, Nov 01 2008

Extensions

Removed incompatibilities with internal OEIS format, extended, R. J. Mathar, Nov 06 2008

Status

approved