157995

Appears in sequences

• Wieferich numbers (1): n > 1 such that 2^A000010(n) == 1 (mod n^2).at n=17A077816
• Number of (n+1) X (n+1) -3..3 symmetric matrices with every 2 X 2 subblock having sum zero and one, three or four distinct values.at n=13A211327
• Numbers n > 1 such that 2^m == 1 (mod n^2), where m = A002326((n-1)/2).at n=13A265630
• Numbers n > 1 such that 2^lambda(n) == 1 (mod n^2), where lambda(n) is the Carmichael lambda function (A002322).at n=14A291961