19470

Appears in sequences

• Number of partitions of n, with two kinds of 1, 2, 3 and 4.at n=21A000710
• Number of partitions of n, with three kinds of 1 and 2 and two kinds of 3,4,5,....at n=15A000714
• dot_product(n,n-1,...2,1)*(6,7,...,n,1,2,3,4,5).at n=38A026063
• Number of points in N^4 of norm <= n.at n=15A055403
• Column m=7 sequence of triangle A103718(n,m), n>=0, without leading zeros.at n=3A103724
• Average of twin-prime pairs for pairs that are expressible as the sum of two triangular numbers.at n=35A117313
• Alkane systems (see Cyvin reference for precise definition).at n=6A121187
• Expansion of q * (psi(q^5) / psi(q))^2 in powers of q where psi() is a Ramanujan theta function.at n=28A138519
• Eleven times hexagonal numbers: a(n) = 11*n*(2*n-1).at n=30A154617
• Expansion of q * (psi(-q^5) / psi(-q))^2 in powers of q where psi() is a Ramanujan theta function.at n=28A210458
• Expansion of 1 + q * (psi(-q^5) / psi(-q))^2 in powers of q where psi() is a Ramanujan theta function.at n=29A228864
• Numbers n such that n is both the average of some twin prime pair p, q (q = p+2) (i.e., n = p+1 = q-1) and is also the arithmetic mean of the four numbers consisting of the two primes before p and the two primes after q.at n=31A256620
• Numbers k such that k is the average of four consecutive primes k-7, k-1, k+1 and k+7.at n=24A258879
• Squarefree numbers n such that n^2 + 1 and n^2 - 1 are semiprime.at n=26A268697
• Zero together with the partial sums of A056640.at n=18A274772
• Number of nX7 0..1 arrays with every element unequal to 0, 1, 2 or 7 king-move adjacent elements, with upper left element zero.at n=7A304229
• Those primitive elements of A337386 that have exactly one primitive nondeficient divisor (A006039).at n=5A341604
• a(n) is the first number k such that there are exactly n primes of the form k + A - B where A and B are sums of subsets of the prime factors of k.at n=16A345316
• a(n) = prime(n)^2 + prime(n+1).at n=33A352851
• Products of 5 distinct primes that are sandwiched between twin prime numbers.at n=11A376380