31901

Appears in sequences

• G.f.: -1 + Product_{k>=1} (1 + prime(k)*x^prime(k)).at n=39A002099
• Number of plane regions after drawing (in general position) a convex n-gon and all its diagonals.at n=29A027927
• Starting index of a string of 4 or more consecutive equal digits in decimal expansion of Pi.at n=29A049516
• Starting index of a string of exactly 4 consecutive equal digits in decimal expansion of Pi.at n=18A049520
• Analog of A006684 for the 5x+1 problem (cf. A133419).at n=19A133423
• Number of 2 X n 0..2 arrays with antidiagonals unimodal and rows and diagonals nondecreasing.at n=21A224000
• Number of nondecreasing -n..n vectors of length 5 whose dot product with some other -n..n vector equals 5.at n=8A226344
• Floor(compositorial(n) / n!), that is, floor(A036691(n) / A000142(n)).at n=13A233447
• a(n) = n^4/6 - 2*n^3/3 - n^2/6 + 5*n/3 + 1.at n=21A299198
• Number of faces in the n-polygon diagonal intersection graph.at n=27A301748
• Pentagonal numbers which are products of three distinct primes.at n=32A381650