27808

Appears in sequences

• Heptagonal (or 7-gonal) pyramidal numbers: a(n) = n*(n+1)*(5*n-2)/6.at n=32A002413
• Numbers whose set of base-12 digits is {1,4}.at n=39A032824
• a(n) = (2*n+1)*(9*n+1).at n=39A033573
• Partial sums of A128379.at n=9A128378
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, 0), (0, 0, 1), (1, 0, -1), (1, 1, 0)}.at n=8A150403
• Number of binary words of length n containing no subword 100001.at n=15A210031
• Even heptagonal pyramidal numbers.at n=23A218325
• Sum of all the parts in the partitions of 4n into 4 parts.at n=10A238328
• Positive integers n such that n=p+q for some primes p,q with pi(p)*pi(q) = sigma(n).at n=26A273286
• Number of flags in an n-dimensional vector space over GF(2).at n=5A289545
• Sum of all the parts in the partitions of n into 4 parts.at n=44A308775
• Composites k such that the concatenation of the prime factors of k, with multiplicity, in some order is divisible by k.at n=45A322843
• Number of Motzkin excursions of length n with an odd number of humps and an even number of peaks.at n=14A325924
• Irregular triangle read by rows. For each j, 1<=j<=n properly color the vertices of a labeled graph on [n] using each of the first j colors in the color set {c1<c2<...<cn}. Orient the edges according to the strict order on the colors. T(n,k) is the number of such directed graphs containing k descents, n>=0, 0<=k<=binomial(n,2).at n=15A381102
• A(n,k) is the sum over all ordered partitions of [n] of k^j for an ordered partition with j inversions; square array A(n,k), n>=0, k>=0, read by antidiagonals.at n=33A381426
• a(n) = Sum_{k=0..floor(n/2)} (-1)^k * binomial(3*n-2*k-3,n-2*k).at n=7A390681