cp's OEIS Frontend

A143677 ( 1, 2, 3, 2^2, 5, 2*3, 7, 2^3, 3^2, 2*5, 11, 2^2*3, 13,..) becomes (abs (1-2, 3-2, 2-5, 2-3, 7-2, 3-3, 2-2, 5-11, 2-2, 3-13,..)).

%I A143677 #7 Mar 01 2021 06:38:39
%S A143677 1,1,3,1,5,0,0,6,0,10,5,2,2,15,1,17,3,4,9,21,0,3,11,0,0,22,1,26,3,8,
%T A143677 15,2,0,1,35,16,11,2,39,4,41,9,1,3,24,2,4,0,3,14,0,40,1,2,9,4,16,27,
%U A143677 57,1,56,29,1,5,1,11,8,65,15,20,3,64,1,1,71,34,3,0,12,9,10,77,1,1,39,81,1,2,15
%N A143677 ( 1, 2, 3, 2^2, 5, 2*3, 7, 2^3, 3^2, 2*5, 11, 2^2*3, 13,..) becomes (abs (1-2, 3-2, 2-5, 2-3, 7-2, 3-3, 2-2, 5-11, 2-2, 3-13,..)).
%e A143677 Abs(1-2)=abs(-1)=1=a(1).
%e A143677 Abs(3-2)=abs(1)=1=a(2).
%e A143677 Abs(2-5)=abs(-3)=3=a(3).
%e A143677 Abs(2-3)=abs(-1)=1=a(4).
%e A143677 Abs(7-2)=abs(5)=5=a(5).
%e A143677 Abs(3-3)=abs(0)=0=a(6).
%e A143677 Abs(2-2)=abs(0)=0=a(7).
%e A143677 Abs(5-11)=abs(-6)=6=a(8).
%e A143677 Abs(2-2)=abs(0)=0=a(9).
%e A143677 Abs(3-13)=abs(-10)=10=a(10), etc.
%p A143677 pflat2 := proc(nmax) local a, ifs, n, p, c ; a := [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)-3 by 2 do printf("%d,", abs(op(n, pL)-op(n+1, pL)) ) ; od: # _R. J. Mathar_, Nov 06 2008
%Y A143677 Cf. A141257, A141261.
%K A143677 nonn,less
%O A143677 1,3
%A A143677 _Juri-Stepan Gerasimov_, Nov 01 2008
%E A143677 Removed incompatibilities with internal OEIS format, extended, _R. J. Mathar_, Nov 06 2008