20120

Appears in sequences

• a(n) is the concatenation of n and 6n.at n=19A009440
• a(n) = A026998(2n+1, n+4).at n=4A027007
• a(n) = greatest number in row n of array T given by A026998.at n=15A027008
• a(n) = T(n, 2*n-8), T given by A027960.at n=11A027970
• Number of partitions of n with equal number of parts congruent to each of 0 and 2 (mod 3).at n=49A035535
• Number of partitions of n into parts not of the form 13k, 13k+2 or 13k-2. Also number of partitions with 1 part of size 1 and differences between parts at distance 5 are greater than 1.at n=45A035950
• Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 2,0,1.at n=4A037519
• In the list of divisors of n (in base 3), each digit 0-2 appears equally often.at n=8A045811
• Multiples of 5 with digit sum 5.at n=38A069540
• Łukasiewicz word for each rooted plane tree (interpretation e in Stanley's exercise 19) encoded by A014486 (or A063171), with the last leaf implicit, i.e., these words are given without the last trailing zero, except for the null tree which is encoded as 0.at n=35A071153
• Totally balanced decimal numbers: if we assign the weight w(d) = d-1 to each digit d (i.e., w(0) = -1, w(1) = 0, ..., w(9) = 8) and then read the digits of the term from left to right, the partial sum of the weights is never negative and the total weighted sum is zero.at n=37A071154
• Łukasiewicz words that are also valid asynchronic siteswap juggling patterns.at n=22A071160
• Integers whose decimal expansion satisfies the condition that if we read each term from the left to right (the most significant to the least significant digit) then each nonzero digit gives a distance to the next nonzero digit to right (with a cyclic wrap-over from the least-significant to the most significant nonzero digit).at n=25A071161
• Consider the succession of single digits of A008585 (multiples of 3): 3 6 9 1 2 1 5 1 8 2 1 2 4 2 7 3 0 .... This sequence gives the lexicographically earliest derangement of A001651 (non-multiples of 3) that produces the same succession of digits.at n=51A097500
• Numbers m having the same sum of divisors as m+20 has.at n=33A181647
• Total sum of the smallest part of every partition of every shell of n.at n=27A196039
• Number of 4 X n -1,1 arrays such that the sum over i=1..4,j=1..n of i*x(i,j) is zero and rows are nondecreasing (ways to put n thrusters pointing east or west at each of 4 positions 1..n distance from the hinge of a south-pointing gate without turning the gate).at n=42A225311
• Numbers n such that sum of decimal digits of n equals number of prime divisors of n counted with multiplicity and sum of distinct decimal digits of n equals number of distinct primes dividing n.at n=12A280911
• Polydivisible nonnegative integers whose decimal digits span an initial interval of {0,...,9}.at n=11A305712
• Numbers k such that 463*2^k+1 is prime.at n=17A323201