

A064460


Number of distinct nonsquarefree entries in nth row of Pascal's triangle.


4



0, 0, 0, 0, 1, 0, 1, 0, 3, 4, 3, 0, 5, 2, 2, 1, 8, 6, 9, 6, 7, 6, 6, 0, 11, 11, 10, 13, 13, 9, 13, 10, 16, 15, 14, 14, 18, 15, 13, 14, 19, 15, 15, 9, 15, 19, 14, 3, 24, 24, 25, 24, 24, 18, 26, 25, 28, 26, 25, 19, 27, 18, 12, 28, 32, 31, 31, 30, 31, 27, 30, 27, 36
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OFFSET

0,9


LINKS

T. D. Noe, Table of n, a(n) for n = 0..1000


FORMULA

a(n) + A238337(n) = A008619(n).  R. J. Mathar, Jan 18 2018


EXAMPLE

a(13) = 2 because C(13,5) = 3^2*11*13 and C(13,6) = 2^2*3*11*13.


MATHEMATICA

f[ n_ ] := (c = 0; k = 1; While[ k < n/2 + .5, If[ Union[ Transpose[ FactorInteger[ Binomial[ n, k ] ] ] [ [ 2 ] ] ] [ [ 1 ] ] > 1, c++ ]; k++ ]; c); Table[ f[ n ], {n, 0, 100} ]


PROG

(PARI) a(n) = sum(k=0, n\2, !issquarefree(binomial(n, k))); \\ Michel Marcus, Mar 05 2014


CROSSREFS

Cf. A048277, A064461, A064462.
Sequence in context: A318840 A318830 A242803 * A108481 A078070 A254745
Adjacent sequences: A064457 A064458 A064459 * A064461 A064462 A064463


KEYWORD

easy,nonn


AUTHOR

Robert G. Wilson v, Oct 02 2001


STATUS

approved



