28434

Appears in sequences

• a(n) is the sum of squares of the first n positive integers congruent to 2 mod 3.at n=20A024394
• Number of positive integers <= 10^n that are divisible by no prime exceeding 23.at n=7A108277
• 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, 1, 0), (0, 0, 1), (0, 1, 0), (1, 0, -1)}.at n=9A149888
• Number of (n+1)X3 0..3 arrays with rows and columns in nondecreasing order and with no 2X2 subblock sum differing from a horizontal or vertical neighbor subblock sum by more than one.at n=5A184088
• Number of (n+1)X7 0..3 arrays with rows and columns in nondecreasing order and with no 2X2 subblock sum differing from a horizontal or vertical neighbor subblock sum by more than one.at n=1A184092
• T(n,k)=Number of (n+1)X(k+1) 0..3 arrays with rows and columns in nondecreasing order and with no 2X2 subblock sum differing from a horizontal or vertical neighbor subblock sum by more than one.at n=22A184095
• T(n,k)=Number of (n+1)X(k+1) 0..3 arrays with rows and columns in nondecreasing order and with no 2X2 subblock sum differing from a horizontal or vertical neighbor subblock sum by more than one.at n=26A184095
• Number of 0..6 arrays x(0..n-1) of n elements with each no smaller than the sum of its four previous neighbors modulo 7.at n=6A200467
• Number of 0..n arrays x(0..6) of 7 elements with each no smaller than the sum of its four previous neighbors modulo (n+1).at n=5A200471
• Number of partitions of n such that each part is no more than 3 more than the sum of all smaller parts.at n=39A286929
• Number of Motzkin trees that are "uniquely closable skeletons".at n=21A300126
• a(n) = numerator of Sum_{d|n} (pod(d)/tau(d)) where pod(k) = the product of the divisors of k (A007955) and tau(k) = the number of the divisors of k (A000005).at n=31A324982
• Expansion of e.g.f. exp( exp(3*(exp(x)-1))-1 ).at n=5A369783