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A121744 Numbers n such that (1 + Sum[Prime[k],{k,1,n}]) = (1 + A007504[n]) divides primorial number p(n)# = Product[Prime[k],{k,1,n}] = A002110[n]. 2
2, 6, 8, 10, 11, 15, 21, 26, 27, 37, 39, 45, 47, 52, 75, 84, 87, 88, 91, 94, 101, 107, 113, 116, 124, 131, 133, 136, 137, 138, 155, 157, 162, 173, 175, 181, 183, 188, 201, 215, 225, 230, 237, 238, 242, 244, 245, 249, 253, 255, 257, 271, 275, 281, 284, 292, 301 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Also a(n) is a set of indices n such that A120291[n] = 1. A120291[n] begins {3,1,11,3,29,1,59,1,101,1,1,3,239,47,1,191,21,251,569,64,1,12,25,482,1061,1,1,...}.

LINKS

Table of n, a(n) for n=1..57.

MATHEMATICA

Select[Range[500], Numerator[(1+Sum[Prime[k], {k, 1, #1}])/Product[Prime[k], {k, 1, #1}]]==1&]

CROSSREFS

Cf. A007504, A002110, A120291.

Sequence in context: A129459 A028772 A325463 * A336986 A198832 A173634

Adjacent sequences:  A121741 A121742 A121743 * A121745 A121746 A121747

KEYWORD

nonn

AUTHOR

Alexander Adamchuk, Aug 19 2006

STATUS

approved

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Last modified June 12 08:13 EDT 2021. Contains 344943 sequences. (Running on oeis4.)