A144136 - OEIS

%I #8 Oct 05 2015 03:01:57

%S 1,5,10,9,13,17,13,14,17,34,7,40,24,24,23,37,24,41,28,32,36,49,31,33,

%T 42,34,11,88,10,94,40,48,54,48,7,76,59,55,45,87,47,93,48,59,53,72,97,

%U 56,59,9,71,56,119,59,63,69,67,80,90,121,10,184,96,12,72,83,71,145,72,89,95

%N (0=0, 1=1, 2=2, 3=3, 4=2^2, 5=5, 6=2*3, 7=7, 8=2^3, 9=3^2, 10=2*5, 11=11, 12=2^2*3, ...) becomes (0+0+1, 1+2+2, 3+3+4, 2+2+5, 5+6+2, 3+7+7, 8+2+3, 9+3+2, 10+2+5, 11+11+12, 2+2+3, ...).

%e 2 + 2 + 3 = 7 = a(11),

%e 13 + 13 + 14 = 40 = a(12),

%e 2 + 7 + 15 = 24 = a(13),

%e 3 + 5 + 16 = 24 = a(14),

%e 2 + 4 + 17 = 23 = a(15),

%e 17 + 18 + 2 = 37 = a(16),

%e 3 + 2 + 19 = 24 = a(17),

%e etc.

%p pflat := proc(nmax) local a, ifs, n, p, c ; a := [0,0,1,1] ; for n from 2 to nmax do a := [op(a),n] ; 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: L := pflat(300) ; for n from 1 to nops(L)-3 by 3 do printf("%d,", op(n,L)+op(n+1,L)+op(n+2,L) ) ; end do: # _R. J. Mathar_, Apr 29 2010

%Y Cf. A002808, A136740, A136811, A143716.

%K nonn

%O 1,2

%A _Juri-Stepan Gerasimov_, Nov 17 2008

%E All numbers after a(14) corrected by _R. J. Mathar_, Apr 29 2010