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 A227697 Numbers of the form ((p^2 + q^2)/2 - 1)/4, where p and q are odd primes. 2
 2, 4, 6, 7, 9, 12, 16, 18, 21, 22, 24, 27, 30, 36, 37, 39, 42, 46, 48, 51, 57, 60, 66, 67, 69, 72, 81, 87, 90, 102, 106, 108, 111, 120, 121, 123, 126, 132, 135, 141, 150, 156, 165, 171, 172, 174, 177, 186, 192, 207, 210 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) mod 3 = 0 if neither prime = 3. a(n) mod 3 = 1 if one prime = 3. a(1) mod 3 = 2 (where both primes = 3). LINKS Table of n, a(n) for n=1..51. FORMULA a(n) = (A143850(n)-1)/4. CROSSREFS Sequence in context: A141437 A219645 A186708 * A097457 A321612 A121865 Adjacent sequences: A227694 A227695 A227696 * A227698 A227699 A227700 KEYWORD nonn AUTHOR Richard R. Forberg, Sep 22 2013 STATUS approved

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Last modified April 14 18:28 EDT 2024. Contains 371667 sequences. (Running on oeis4.)