A043347 To form the sequence, write the primes 2, 3, 5, 7,... as an infinite string 2357111317...; then take the first 2 digits of the string, 23, then the next 3 digits, 571, then the next 5 digits, 11317, then the next 7 digits, 1923293, then... (stepping through prime numbers of digits). Omit any leading 0's.

23, 571, 11317, 1923293, 13741434753, 5961677173798, 38997101103107109, 1131271311371391491, 51157163167173179181191, 19319719921122322722923323924, 1251257263269271277281283293307

Offset

1,1

Links

Table of n, a(n) for n=1..11.

Mathematica

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]]]]); Table[ a[n], {n, 1, 13} ]

Crossrefs

The first four terms of the sequence are primes - see A066776.

Sequence in context: A196536 A231261 A242358 * A015696 A106538 A203102

Adjacent sequences: A043344 A043345 A043346 * A043348 A043349 A043350

Keyword

nonn,base

Author

Joseph L. Pe, Jan 12 2002

Extensions

More terms from Robert G. Wilson v, Jan 16 2002

Status

approved