90100

Appears in sequences

• 2nd elementary symmetric function of the first n+1 positive integers congruent to 2 mod 3.at n=15A024391
• Number of hands that peg n points in the "show" phase of 6-card cribbage.at n=14A066354
• Triangular numbers with sum of digits = 10.at n=36A068129
• Triangular numbers in which neighboring digits differ at most by 1. Allowed neighbors of 9 are 0, 8 and 9.at n=19A068149
• a(1) = 1; a(n) is the smallest triangular number > a(n-1) which differs from it at every digit.at n=36A068855
• Number of 3 X n binary matrices avoiding simultaneously the right angled numbered polyomino patterns (ranpp) (00;1) and (11;0).at n=10A099944
• Triangular numbers all of whose digits are nonprimes.at n=39A111484
• Triangular numbers whose digit reversal is prime; trailing zeros are permitted.at n=25A115704
• Triangular numbers for which the number of divisors is also a triangular number.at n=27A116541
• Triangular numbers composed of digits {0,1,9}.at n=8A119047
• Numbers k such that k and k^2 use only the digits 0, 1, 4, 8 and 9.at n=43A136867
• Numbers k such that k and k^2 use only the digits 0, 1, 5, 8 and 9.at n=29A136874
• Numbers k such that k and k^2 use only the digits 0, 1, 6, 8 and 9.at n=31A136879
• Numbers k such that k and k^2 use only the digits 0, 1, 7, 8 and 9.at n=31A136880
• Numbers k such that k and k^2 use only the digits 0, 1, 8 and 9.at n=29A136881
• Composite numbers n with k digits such that each sum of 1 to k digits of n is substring of n.at n=46A205530
• Triangular numbers divisible by the square of the sum of their digits.at n=9A243008
• Triangular numbers that are sum of squares of two distinct triangular numbers.at n=24A346386
• Numbers that start a run of four consecutive triangular numbers with four distinct prime factors.at n=21A349773
• a(n) = Sum_{k=0..floor(n/4)} binomial(n-3*k-1,k) * binomial(k,n-4*k).at n=41A383584