44253

Appears in sequences

• 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=21A073873
• a(n) = A000217(A000041(n)).at n=17A086737
• Concatenation of triangular number k and its 10's complement is prime.at n=18A108970
• Triangular numbers for which the sum of the digits is a heptagonal number.at n=36A117312
• Hexagonal numbers with prime indices.at n=34A117961
• Triangular numbers t such that t+10 is a prime.at n=38A129755
• Triangular numbers which are leg of a Pythagorean triple with hypotenuse in A213188.at n=42A213189
• Triangular array: row n gives the coefficients of the polynomial p(n,x) defined in Comments.at n=49A249248
• Numbers k such that sopfr(k + sopfr(k)) = sopfr(k) + sopfr(sopfr(k)), where sopfr = A001414.at n=42A376851