A201156 Row sums of triangle A201146.

1, 3, 10, 11, 56, 57, 400, 401, 402, 403, 4434, 4435, 57656, 57657, 57658, 57659, 980204, 980205, 18623896, 18623897, 18623898, 18623899, 428349678, 428349679, 428349680, 428349681, 428349682, 428349683, 12422140808, 12422140809, 385086365080, 385086365081

Offset: 1

Author

Arkadiusz Wesolowski, Nov 27 2011

Keywords

• nonn

Comments

a(n) = a(n-1) + 1 if and only if n is a composite number.

Links

• Arkadiusz Wesolowski, Table of n, a(n) for n = 1..502

Crossrefs

Cf. A201146.

Programs

Mathematica

Table[Sum[Product[Prime[i], {i, PrimePi[n]}]/Product[Prime[i], {i, PrimePi[k]}], {k, n}], {n, 32}]