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A014369
a(n) = bcd, where n = C(b,3)+C(c,2)+C(d,1), b>c>d>=0.
2
310, 320, 321, 410, 420, 421, 430, 431, 432, 510, 520, 521, 530, 531, 532, 540, 541, 542, 543, 610, 620, 621, 630, 631, 632, 640, 641, 642, 643, 650, 651, 652, 653, 654, 710, 720, 721, 730, 731, 732, 740, 741, 742, 743, 750, 751, 752, 753
OFFSET
1,1
COMMENTS
In the definition bcd means concatenation not multiplication. - Sean A. Irvine, Oct 18 2018
REFERENCES
W. Bruns and J. Herzog, Cohen-Macaulay Rings, Cambridge, 1993, p. 158.
MAPLE
invA000292 := proc(n)
local i;
for i from 1 do
if binomial(i+1, 3) > n then
return i;
end if;
end do:
end proc:
invA000217 := proc(n)
local i;
for i from 1 do
if binomial(i+1, 2) > n then
return i;
end if;
end do:
end proc:
A014369 := proc(n)
local b, c, d ;
b := invA000292(n) ;
c := invA000217(n-binomial(b, 3)) ;
d := n-binomial(b, 3)-binomial(c, 2) ;
digcatL([b, c, d]) ; # of program transforms
end proc:
seq(A014369(n), n=1..70) ; # R. J. Mathar, May 25 2023
CROSSREFS
Sequence in context: A105841 A127456 A114484 * A273593 A051981 A134549
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
a(1), a(4), a(10), a(20), a(35) modified to meet constraint b>c>d and more terms from Sean A. Irvine, Oct 18 2018
STATUS
approved