A141089 Integral quotients of products of consecutive composites divided by their sums: Last consecutive composite.

4, 9, 14, 18, 22, 25, 26, 33, 48, 49, 78, 80, 84, 95, 105, 110, 114, 115, 119, 123, 124, 129, 147, 150, 152, 158, 160, 170, 175, 184, 190, 200, 202, 212, 213, 242, 245, 250, 256, 258, 272, 284, 287, 288, 291, 306, 309, 314, 319, 327, 332, 333, 336, 342, 343

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

Find the products and sums of consecutive composites. When the products divided by the sums produce integral quotients, add terms to sequence.

Example

a(3) = 14 because 4*6*8*9*10*12*14 = 2903040 and 4+6+8+9+10+12+14 = 63; 2903040/63 = 46080, integral -- 14 is added to the sequence.

Mathematica

comp = Select[Range[500], CompositeQ]; comp[[Position[Rest @ FoldList[Times, 1, comp]/Accumulate[comp], _?IntegerQ] // Flatten]] (* Amiram Eldar, Jan 12 2020 *)

Crossrefs

Cf. A141090, A141091, A141092.

Compare with A140761, A159578, A140763, A116536.

Sequence in context: A313020 A313021 A313022 * A313023 A313024 A313025

Adjacent sequences: A141086 A141087 A141088 * A141090 A141091 A141092

Keyword

easy,nonn

Author

Enoch Haga, Jun 01 2008

Status

approved