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 A123572 The Kruskal-Macaulay function K_3(n). 3
 0, 3, 5, 6, 6, 8, 9, 9, 10, 10, 10, 12, 13, 13, 14, 14, 14, 15, 15, 15, 15, 17, 18, 18, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 21, 23, 24, 24, 25, 25, 25, 26, 26, 26, 26, 27, 27, 27, 27, 27, 28, 28, 28, 28, 28, 28, 30, 31, 31, 32, 32, 32, 33, 33, 33, 33, 34, 34, 34, 34, 34 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Write n (uniquely) as n = C(n_t,t) + C(n_{t-1},t-1) + ... + C(n_v,v) where n_t > n_{t-1} > ... > n_v >= v >= 1. Then K_t(n) = C(n_t,t-1) + C(n_{t-1},t-2) + ... + C(n_v,v-1). REFERENCES D. E. Knuth, The Art of Computer Programming, Vol. 4, Fascicle 3, Section 7.2.1.3, Table 3. LINKS MAPLE lowpol := proc(n, t) local x::integer ; x := floor( (n*factorial(t))^(1/t)) ; while binomial(x, t) <= n do x := x+1 ; od ; RETURN(x-1) ; end: C := proc(n, t) local nresid, tresid, m, a ; nresid := n ; tresid := t ; a := [] ; while nresid > 0 do m := lowpol(nresid, tresid) ; a := [op(a), m] ; nresid := nresid - binomial(m, tresid) ; tresid := tresid-1 ; od ; RETURN(a) ; end: K := proc(n, t) local a ; a := C(n, t) ; add( binomial(op(i, a), t-i), i=1..nops(a)) ; end: A123572 := proc(n) K(n, 3) ; end: for n from 0 to 80 do printf("%d, ", A123572(n)) ; od ; # R. J. Mathar, May 18 2007 CROSSREFS For K_i(n), i=1, 2, 3, 4, 5 see A000012, A003057, A123572, A123573, A123574. Sequence in context: A281591 A267884 A077859 * A244953 A076819 A181757 Adjacent sequences:  A123569 A123570 A123571 * A123573 A123574 A123575 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Nov 12 2006 EXTENSIONS More terms from R. J. Mathar, May 18 2007 STATUS approved

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Last modified March 19 23:02 EDT 2019. Contains 321343 sequences. (Running on oeis4.)