1,2

Numbers m such that Ad(m) = A000203(m) / A000005(m) = A057020(m) / A057021(m) and Ah(m) = A023896(m) / A000010(m) = A026741(m) / A040001(m-1) both integer. a(n) = number 1 and even arithmetic numbers from A003601. Subsequence of A003601. Union a(n) and A175679(n+1) = A003601(n) (arithmetic numbers).

Table of n, a(n) for n=1..34.

a(2) = 6, Ad(6) = (1+2+3+6)/4 = 3, Ah(6) = (1+5)/2 = 3, Ad(6) and Ah(6) both integer.

Sequence in context: A037177 A255217 A048747 * A173870 A101567 A123267

Adjacent sequences: A175675 A175676 A175677 * A175679 A175680 A175681

nonn

Jaroslav Krizek, Aug 07 2010

approved