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 A114023 Squares of the form semiprime(n) + n-th triangular number. 0
 4, 16, 100, 144, 33489, 82369, 41088506209, 95056905969, 196978855329, 4901432910724, 6047212155664, 26601838343809, 247869502464123136 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(14) > 10^18. - Donovan Johnson, Jun 04 2013 LINKS FORMULA a(n) = semiprime(k) + k(k+1)/2 when this is a square. PROG (PARI) lista(nn) = {n = -1; for (i=1, nn, if (bigomega(i) == 2, n++; if (issquare(sq=i + n*(n+1)/2), print1(sq, ", ")); ); ); } \\ Michel Marcus, Jun 03 2013 CROSSREFS Cf. A000217, A111440, A112662. Sequence in context: A209299 A091040 A029985 * A145823 A121142 A318693 Adjacent sequences:  A114020 A114021 A114022 * A114024 A114025 A114026 KEYWORD nonn AUTHOR Giovanni Teofilatto, Feb 01 2006 EXTENSIONS More terms from Michel Marcus, Jun 03 2013 a(7)-a(13) from Donovan Johnson, Jun 04 2013 STATUS approved

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Last modified January 18 20:57 EST 2019. Contains 319282 sequences. (Running on oeis4.)