23436

Appears in sequences

• Number of ways of placing n non-attacking bishops on an n X n board so that every square is attacked (or occupied).at n=10A005635
• Coordination sequence for 4-dimensional I-centered cubic orthogonal lattice.at n=18A008532
• Expansion of Product_{m >= 1} (1-m*q^m)^12.at n=12A022672
• Number of reversible strings with n beads using a maximum of six different colors.at n=6A056308
• Number of Gnutella users reachable with given connections and hops.at n=60A067066
• Triangular numbers whose index is a multiple of the sum of their digits.at n=38A067520
• Triangular numbers with property that digits alternate in parity.at n=31A068882
• Triangular numbers with property that digits alternate in parity individually as well as in concatenation with previous terms.at n=17A068889
• Triangular numbers of the form 21*k.at n=41A069499
• a(n) = (n^6 + n^3)/2.at n=6A071232
• Triangular numbers which are 7-almost primes.at n=13A076581
• Smaller of the two successive triangular numbers which differ in the use of only one digit.at n=37A077759
• Numbers k such that 2^k - 1 is divisible by (k-1).at n=22A087965
• Triangle read by rows in which the n-th row contains the n smallest triangular numbers with the least significant digits of the n-th triangular number.at n=33A095225
• Triangular numbers that are sums of two consecutive primes.at n=26A111163
• Triangle read by rows, T(n, k) = Sum_{j=0..n} C(n-j, n-k)*E2(n, j), where E2 are the second-order Eulerian numbers A201637, for n >= 0 and 0 <= k <= n.at n=38A112493
• Third column of triangle A112493 used for e.g.f.s of Stirling2 diagonals.at n=6A112495
• Triangular numbers for which the sum of the digits is a heptagonal number.at n=25A117312
• Triangular numbers n divisible by the number of triangular numbers smaller than n.at n=36A117519
• Triangle read by rows: T(n,k) is the number of partitions of an n-set having k blocks of size > 1 (0<=k<=floor(n/2)).at n=32A124324