21786

Appears in sequences

• Number of subsequences of {1..n} such that all differences of pairs of terms are distinct (i.e., number of Golomb rulers on {1..n}).at n=23A054578
• Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,21.at n=28A064247
• Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,25.at n=6A064249
• Expansion of eta(q^6) * eta(q^10) / (eta(q) * eta(q^15)) in powers of q.at n=41A094023
• Stable Poincaré series [or Poincare series] for Lie group of type A (i.e., the variety of complex nonsingular k X k matrices with distinct eigenvalues).at n=18A098788
• Expansion of q * (chi(-q^3) * chi(-q^5)) / (chi(-q) * chi(-q^15))^2 in powers of q where chi() is a Ramanujan theta function.at n=40A123630
• Triangle, read by rows, of the limit of coefficients of q in {[x^m] W(x,q)} as m grows when arranged into a triangle where row n is multiplied by n! for n>=1.at n=16A126343
• Expansion of q * chi(q^3) * chi(q^5) / (chi(q) * chi(q^15))^2 in powers of q where chi() is a Ramanujan theta function.at n=40A145786
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 126", based on the 5-celled von Neumann neighborhood.at n=42A270215
• Expansion of Sum_{k>=1} x^k / (1 - k * x^k)^k.at n=20A324158