64261

Appears in sequences

• n written in fractional base 8/6.at n=41A024648
• Denominators of continued fraction convergents to sqrt(448).at n=4A041853
• a(n) = 2^n*Sum_{k=0..n} (n+k)!/((n-k)!*k!*4^k).at n=6A043301
• Triangular numbers which are the product of two primes.at n=23A068443
• Triangular numbers which are one more than a product of distinct triangular numbers.at n=26A083517
• Number of Motzkin paths of length n with no peaks at level 1.at n=14A089372
• Triangle read by rows: T(n,k) is number of Motzkin paths of length n having k peaks at height 1.at n=56A097611
• Concatenation of triangular number k and its 10's complement is prime.at n=22A108970
• Triangular numbers that are also brilliant (A078972).at n=16A113940
• Semiprimes in A006987(n), or semiprime binomial coefficients: C(n,k), 2 <= k <= n-2.at n=24A124000
• Triangular numbers T such that T+10 is the next prime after T.at n=11A129540
• Product p*q of two primes with q = 2*p + 1.at n=13A156592
• Carryless squares of carryless primes (cf. A169887).at n=31A169904
• Semiprimes of form p*q with p < q, such that 2^p - 1 == 0 (mod q).at n=15A179768
• Number of Dyck n-paths all of whose ascents and descents have lengths equal to 1 (mod 5).at n=27A212364
• Triangular numbers of the form k^2 + k - 1.at n=3A217758
• Primitive numbers in A229307.at n=34A229311
• Numbers n such that A229964(n) = 1.at n=16A229965
• Squarefree numbers (from A005117) with prime divisors in a 2p+1 progression.at n=18A231966
• Triangular numbers (A000217) that are also centered heptagonal numbers (A069099).at n=2A253880