23421

Appears in sequences

• Convolution of odd numbers and primes.at n=27A023662
• Numbers having four 5's in base 8.at n=28A043444
• Numbers n such that Maple 9.5, Maple 10, Maple 11 and Maple 12 give the wrong answers for the number of partitions of n.at n=22A110375
• Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having k increasing even cycles (0<=k<=n). A cycle (b(1), b(2), ...) is said to be increasing if, when written with its smallest element in the first position, it satisfies b(1)<b(2)<b(3)<... . A cycle is said to be even if it has an even number of entries. For example, the permutation (18)(2347)(569) has 2 increasing even cycles.at n=20A186764
• Number of permutations of {1,2,...,n} having no increasing even cycles. A cycle (b(1), b(2), ...) is said to be increasing if, when written with its smallest element in the first position, it satisfies b(1)<b(2)<b(3)<... . A cycle is said to be even if it has an even number of entries.at n=8A186765
• Number of (w,x,y,z) with all terms in {1,...,n} and |w-x| <= |x-y| + |y-z|.at n=13A212572
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 737", based on the 5-celled von Neumann neighborhood.at n=25A273480
• Numbers n such that the decimal equivalent of the binary reflected Gray code representation of n is a palindromic prime.at n=45A281382
• Numbers m such that 20*m + 1, 80*m + 1, 100*m + 1, and 200*m + 1 are all primes.at n=29A372186