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A069291 Number of square divisors of n <= sqrt(n). 3
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 1, 2, 1, 1, 1, 3, 1, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,16

COMMENTS

Terms 1, 2, 3, ... occurs for the first time at 1, 16, 108, 288, 1296, 3600, 10368, 14400, ... - Antti Karttunen, Nov 20 2017

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384

MATHEMATICA

Table[DivisorSum[n, 1 &, And[IntegerQ@ Sqrt@ #, # <= Sqrt@ n] &], {n, 120}] (* Michael De Vlieger, Nov 20 2017 *)

PROG

(PARI) A069291(n) = sumdiv(n, d, (issquare(d)&&((d^2)<=n))); \\ Antti Karttunen, Nov 20 2017

CROSSREFS

Cf. A000188, A035316, A046951, A069290, A069292, A069293.

Sequence in context: A164117 A177704 A138191 * A268238 A081117 A129252

Adjacent sequences:  A069288 A069289 A069290 * A069292 A069293 A069294

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Mar 14 2002

EXTENSIONS

More terms from Antti Karttunen, Nov 20 2017

STATUS

approved

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Last modified December 12 23:21 EST 2019. Contains 329963 sequences. (Running on oeis4.)