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Search: id:A063937
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| A063937 |
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Sum of unitary divisors of n is a square > 1. |
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+0
2
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| 3, 8, 22, 24, 66, 70, 76, 94, 115, 119, 170, 210, 214, 217, 228, 252, 265, 282, 310, 316, 322, 345, 357, 382, 385, 490, 497, 510, 517, 522, 527, 580, 612, 642, 651, 679, 710, 716, 742, 745, 782, 795, 801, 833, 862, 889, 920, 930, 935, 948, 952, 966, 970
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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A unitary divisor of n is a divisor d of n such that gcd(d, n/d)=1.
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,1000
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EXAMPLE
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The unitary divisors of 3 are 1,3 and then 3+1=4 is a square
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PROGRAM
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(PARI) us(n) = sumdiv(n, d, if(gcd(d, n/d)==1, d)) { n=0; for (m=1, 10^9, u=us(m); if (issquare(u) && u > 1, write("b063937.txt", n++, " ", m); if (n==1000, break)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 03 2009]
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CROSSREFS
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Cf. A034448, A063936.
Sequence in context: A148769 A156291 A111136 this_sequence A027211 A027235 A086596
Adjacent sequences: A063934 A063935 A063936 this_sequence A063938 A063939 A063940
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KEYWORD
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easy,nice,nonn
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AUTHOR
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Felice Russo (felice.russo(AT)katamail.com), Aug 31 2001
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