212325

Appears in sequences

• Let N = 1357911131517192123252729313335373941434547495153555759616365676971..., the concatenation of the odd numbers. a(n) is the n-digit number formed from the digits of N starting from the {n(n-1)/2 +1}th digit. Omit any leading zeros.at n=5A066553
• Square array read by antidiagonals upwards: the n-th row o.g.f. is exp( Sum_{i >= 1} d(n,i+1)*x^i/i ) for n >= 1, where d(n,k) is Shanks's array of generalized Euler and class numbers.at n=30A262144