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A201156 Row sums of triangle A201146. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

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

MATHEMATICA

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

CROSSREFS

Cf. A201146.

Sequence in context: A119221 A119219 A125569 * A309525 A253807 A212993

Adjacent sequences:  A201153 A201154 A201155 * A201157 A201158 A201159

KEYWORD

nonn

AUTHOR

Arkadiusz Wesolowski, Nov 27 2011

STATUS

approved

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Last modified June 24 21:50 EDT 2021. Contains 345433 sequences. (Running on oeis4.)