20301

Appears in sequences

• Row sums of triangle A060923 (even part of bisection of Lucas triangle).at n=6A060926
• Triangular numbers with sum of digits = 6.at n=6A068128
• Smallest triangular number with value of the internal digits = n; or 0 if no such number exists.at n=30A069692
• Number of vertically indecomposable distributive lattices on n nodes.at n=25A072361
• Terms of A073872 that do not change their position in the rearrangement; i.e., values of A073872(n) which equal n(n+1)/2.at n=14A073873
• Triangular numbers whose sum of prime factors (with repetition) is also triangular.at n=19A076169
• Smaller of the two successive triangular numbers which differ in the use of only one digit.at n=36A077759
• Third row of Pascal-(1,6,1) array A081581.at n=29A081591
• Triangular numbers in which the sum of the external digits equals the sum of the internal digits.at n=12A088289
• Numbers k such that the decimal digits of phi(k) are a permutation of those of k.at n=24A115921
• Hexagonal numbers for which the sum of the digits is also a hexagonal number.at n=21A117062
• Hexagonal numbers for which both the sum of the digits and the product of the digits are also hexagonal numbers.at n=11A117064
• Triangular numbers for which the sum of the digits is a hexagonal number.at n=40A117309
• Hexagonal numbers with prime indices.at n=25A117961
• Numbers such that the digital sums in bases 2, 3, 5 and 7 all are equal.at n=24A135127
• Indices k such that A020507(k)=Phi[k](-8) is prime, where Phi is a cyclotomic polynomial.at n=33A138922
• Triangular numbers n*(n+1)/2 with n and n+1 composite, where number of prime factors in n = number of prime factors in n+1. (Prime factors are counted with multiplicity.)at n=34A144486
• a(n) = (prime(n))^2 - (nonprime(n))^2.at n=35A161757
• Number of arrays of 5 integers in -n..n with sum zero and equal numbers of elements greater than zero and less than zero.at n=9A201813
• Base 2i representation of nonnegative integers.at n=21A212494