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 A175915 Odd terms of A109510. 0
 2205, 312896925, 1874196225, 3356107425, 4181881725, 4987853325, 6946213725, 8860349025, 13250605725, 17989980525, 25443641025, 32177090925, 38286871425, 55531730925, 75756402225, 113679103725, 152738872209, 170812073025, 179835853725, 186091427025 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(1)=2205=A109510(29), a(2)-a(8) from Max Alekseyev. sqrt(sigma(a(n))-2*a(n)): 6, 3432, 8250, 11022, 19376. LINKS Table of n, a(n) for n=1..20. PROG (PARI) is(n)=n%2&&issquare(sigma(n)-2*n) \\ Charles R Greathouse IV, Dec 06 2011 CROSSREFS Cf. A109510 sigma(n)-2n is a square. Sequence in context: A348743 A252397 A252392 * A098192 A004931 A004951 Adjacent sequences: A175912 A175913 A175914 * A175916 A175917 A175918 KEYWORD nonn AUTHOR Zak Seidov, Oct 15 2010 EXTENSIONS a(6)-a(18) from Donovan Johnson, Oct 17 2010 a(19)-a(20) from Donovan Johnson, Dec 06 2011 STATUS approved

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Last modified September 29 20:04 EDT 2023. Contains 365777 sequences. (Running on oeis4.)