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A081214 Least m such that A081212(m) = n. 3
1, 4, 12, 84, 3948, 88320, 815424 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..7.

MAPLE

gsqfree := proc(n) local resul ; resul := n ; while not numtheory[issqrfree](resul) do resul := resul-1 ; od ; RETURN(resul) ; end: A081210 := proc(n) option remember ; local pfd, resul, p ; if n = 1 then RETURN(1) ; else pfd := ifactors(n)[2] ; resul := 1 ; for p from 1 to nops(pfd) do resul := resul*gsqfree( op(1, op(p, pfd))^op(2, op(p, pfd))) ; od ; fi ; end: r := proc(n, k) option remember ; if k= 0 then n ; else r(A081210(n), k-1) ; fi ; end: A081212 := proc(n) local i; i := 0 ; while r(n, i) <> r(n, i+1) do i := i+1 ; od ; RETURN(i) ; end: A081214 := proc() local a, m, h ; a :=[seq(-1, i=1..40)] ; for m from 1 to 8000000 do h := A081212(m) ; if h+1 <= nops(a) then if op(h+1, a) = -1 then a := subsop(h+1=m, a) ; print(a) ; fi ; fi ; od ; RETURN(a) ; end: A081214() ; # R. J. Mathar, Apr 04 2007

CROSSREFS

Cf. A081210.

Sequence in context: A263866 A208802 A226960 * A331087 A194004 A064280

Adjacent sequences:  A081211 A081212 A081213 * A081215 A081216 A081217

KEYWORD

nonn,more

AUTHOR

Reinhard Zumkeller, Mar 10 2003

EXTENSIONS

More terms from R. J. Mathar, Apr 04 2007

STATUS

approved

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Last modified August 9 21:08 EDT 2022. Contains 356026 sequences. (Running on oeis4.)