1,2

A043347(170) already has over a thousand digits.

a[n_] := (k = Prime[ Floor[n^(3/2)]] + 6; l = Sum[ Prime[i], {i, 1, n - 1} ]; b = ""; Do[ b = StringJoin[b, ToString[ Prime[i]]], {i, 1, k} ]; Return[ ToExpression[ StringTake[ StringDrop[b, l], Prime[n]]]]); Do[ If[ PrimeQ[ a[n]], Print[n]], {n, 1, 180} ]

Sequence in context: A097930 A012322 A076519 this_sequence A115901 A073325 A037395

Adjacent sequences: A066773 A066774 A066775 this_sequence A066777 A066778 A066779

base,hard,nonn

Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Jan 14 2002