21507

Appears in sequences

• a(n) = a(n-1) + a(n - 1 minus the number of terms of a(k) == (mod 4) so far).at n=35A060731
• Number of perfect squared squares of order n up to symmetries of the square and of its squared subrectangles, if any.at n=29A181735
• Triangle of coefficients of polynomials u(n,x) jointly generated with A210804; see the Formula section.at n=49A210803
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 942", based on the 5-celled von Neumann neighborhood.at n=34A273797
• a(n) = 2*A090495(n) - 1.at n=41A274297
• a(1) = 1; a(n) = Sum_{d|n, d < n} p(n/d) * a(d), where p = A000041 (partition numbers).at n=35A328424
• Numbers that are the sum of seven fourth powers in six or more ways.at n=33A345572
• Numbers that are the sum of seven fourth powers in seven or more ways.at n=8A345573
• Numbers that are the sum of seven fourth powers in eight or more ways.at n=4A345574
• Numbers that are the sum of seven fourth powers in exactly eight ways.at n=1A345830
• Fixed points in A375564.at n=25A376584