20573

Appears in sequences

• Expansion of Sum_{n>=1} ((n-1) * q^(n*(n+1)/2) / Product_{k=1..n} (1 - q^k)).at n=52A218074
• 2^(p-1) modulo p^3, where p = prime(n).at n=11A271234
• Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n-1) + b(n-2) + 1, where a(0) = 1, a(1) = 2, b(0) = 3, and (a(n)) and (b(n)) are increasing complementary sequences.at n=16A294551
• The number of distinct positions on an infinite chessboard reachable by the (3,4)-leaper in <= n moves.at n=19A297741
• a(n) is the number of terms in the analog of A121805 but starting with n, or -1 if that sequence is infinite.at n=9A330128
• a(n) is the number of terms in the analog of A121805 but starting with A037124(n), or -1 if that sequence is infinite.at n=9A367601
• Lesser of 2 successive squarefree semiprimes (k, k+5) sandwiching 4 consecutive nonsquarefree numbers.at n=3A368589