proposed

approved

editing

proposed

a(n) = A071178(A002808(n)). [From _- _R. J. Mathar_, Oct 27 2009]

a(1)=2 (4=2*2); a(2)=1 (6=2*3); a(3)=3 (8=2*2*2); a(4)=2 (9=3*3); a(5)=1 (10=2*5); a(6)=1 (12=2*2*3).

a(1)=2 (4 = 2*2);

a(2)=1 (6 = 2*3);

a(3)=3 (8 = 2*2*2);

a(4)=2 (9 = 3*3);

a(5)=1 (10 = 2*5);

a(6)=1 (12 = 2*2*3).

A002808 := proc(n) local n ; if n = 1 then 4; else for a from procname(n-1)+1 do if not isprime(a) then return a; end if; end do ; end if; end proc; A071178 := proc(n) local p, e, ps, i ; p := -1 ; e := 0 ; ps := ifactors(n)[2] ; for i from 1 to nops(ps) do if op(1, op(i, ps)) > p then p := op(1, op(i, ps)) ; e := op(2, op(i, ps)) ; fi; od: return e ; end proc: A166949 := proc(n) A071178(A002808(n)) ; end proc : seq(A166949(n), n=1..100) ; [From _# _R. J. Mathar_, Oct 27 2009]

approved

editing

_Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), _, Oct 25 2009

a(n)=A071178(A002808(n)). [From _R. J. Mathar (mathar(AT)strw.leidenuniv.nl), _, Oct 27 2009]

A002808 := proc(n) local n ; if n = 1 then 4; else for a from procname(n-1)+1 do if not isprime(a) then return a; end if; end do ; end if; end proc; A071178 := proc(n) local p, e, ps, i ; p := -1 ; e := 0 ; ps := ifactors(n)[2] ; for i from 1 to nops(ps) do if op(1, op(i, ps)) > p then p := op(1, op(i, ps)) ; e := op(2, op(i, ps)) ; fi; od: return e ; end proc: A166949 := proc(n) A071178(A002808(n)) ; end proc : seq(A166949(n), n=1..100) ; [From _R. J. Mathar (mathar(AT)strw.leidenuniv.nl), _, Oct 27 2009]

The count of largest prime factors in n-th composite.

2, 1, 3, 2, 1, 1, 1, 1, 4, 2, 1, 1, 1, 1, 2, 1, 3, 1, 1, 5, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 6, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 1, 7, 1, 1, 1, 1, 1, 1, 1, 1, 1

1,1

a(n)=A071178(A002808(n)). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 27 2009]

a(1)=2 (4=2*2); a(2)=1 (6=2*3); a(3)=3 (8=2*2*2); a(4)=2 (9=3*3); a(5)=1 (10=2*5); a(6)=1 (12=2*2*3).

A002808 := proc(n) local n ; if n = 1 then 4; else for a from procname(n-1)+1 do if not isprime(a) then return a; end if; end do ; end if; end proc; A071178 := proc(n) local p, e, ps, i ; p := -1 ; e := 0 ; ps := ifactors(n)[2] ; for i from 1 to nops(ps) do if op(1, op(i, ps)) > p then p := op(1, op(i, ps)) ; e := op(2, op(i, ps)) ; fi; od: return e ; end proc: A166949 := proc(n) A071178(A002808(n)) ; end proc : seq(A166949(n), n=1..100) ; [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 27 2009]

Cf. A002808.

nonn

Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Oct 25 2009

approved