A126256 Number of distinct terms in rows 0 through n of Pascal's triangle.
1, 1, 2, 3, 5, 7, 9, 12, 16, 20, 24, 29, 35, 41, 48, 53, 60, 68, 77, 86, 95, 103, 114, 125, 137, 149, 162, 175, 188, 202, 217, 232, 248, 264, 281, 297, 314, 332, 351, 370, 390, 410, 431, 452, 474, 495, 518, 541, 565, 589, 614, 639, 665, 691, 718, 744, 770, 798
Offset: 0
Examples
There are 9 distinct terms in rows 0 through 6 of Pascal's triangle (1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 6, 4, 1, 1, 5, 10, 10, 5, 1, 1, 6, 15, 20, 15, 6, 1); hence a(6)=9.
Links
- Nick Hobson, Table of n, a(n) for n = 0..1000
- Nick Hobson, Python program for this sequence
Programs
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Haskell
-- import Data.List.Ordered (insertSet) a126256 n = a126256_list !! n a126256_list = f a007318_tabl [] where f (xs:xss) zs = g xs zs where g [] ys = length ys : f xss ys g (x:xs) ys = g xs (insertSet x ys) -- Reinhard Zumkeller, May 26 2015, Nov 09 2011
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Maple
seq(nops(`union`(seq({seq(binomial(n,k),k=0..n)},n=0..m))),m=0..57); # Emeric Deutsch, Aug 26 2007
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Mathematica
Table[Length[Union[Flatten[Table[Binomial[n,k],{n,0,x},{k,0,n}]]]],{x,0,60}] (* Harvey P. Dale, Sep 10 2022 *)
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PARI
lim=57; z=listcreate(1+lim^2\4); for(n = 0, lim, for(r=1, n\2, s=Str(binomial(n, r)); f=setsearch(z, s, 1); if(f, listinsert(z, s, f))); print1(1+#z, ", "))
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Python
def A126256(n): s, c = (1,), {1} for i in range(n): s = (1,)+tuple(s[j]+s[j+1] for j in range(len(s)-1)) + (1,) c.update(set(s)) return len(c) # Chai Wah Wu, Oct 17 2023
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