A324915 a(n) = Sum_{k=1..n} 2^k * sigma(k), where sigma(k) = A000203(k).

2, 14, 46, 158, 350, 1118, 2142, 5982, 12638, 31070, 55646, 170334, 285022, 678238, 1464670, 3496286, 5855582, 16079198, 26564958, 70605150, 137714014, 288708958, 490035550, 1496668510, 2536855902, 5355428190, 10724137310, 25756522846, 41862650206, 119172061534

Offset: 1

Author

Vaclav Kotesovec, Mar 18 2019

Keywords

• nonn

Links

• Vaclav Kotesovec, Plot of a(n)/(n*2^n) for n = 1..100000
• Eric Weisstein's World of Mathematics, Divisor Function

Crossrefs

Cf. A000203, A024916, A185003, A324914.

Programs

Mathematica

Accumulate[Table[2^k*DivisorSigma[1, k], {k, 1, 30}]]