A136420 List of primes with digits grouped into clumps of four. Leading zeros are not printed.

2357, 1113, 1719, 2329, 3137, 4143, 4753, 5961, 6771, 7379, 8389, 9710, 1103, 1071, 911, 3127, 1311, 3713, 9149, 1511, 5716, 3167, 1731, 7918, 1191, 1931, 9719, 9211, 2232, 2722, 9233, 2392, 4125, 1257, 2632, 6927, 1277, 2812, 8329, 3307, 3113, 1331

Offset

1,1

References

Clifford A. Pickover, A Passion for Mathematics, Wiley, 2005; see p. 63.

Links

Table of n, a(n) for n=1..42.

Maple

A055642 := proc(n) if n = 0 then 1 ; else ilog10(n)+1 ; fi ; end: cat2 := proc(a, b) a*10^A055642(b)+b ; end: A136420 := proc(nmax) local p, bigpr, a, nodigs, bigprlen; p := 2 ; bigpr := 0 ; bigprlen := 0 ; a := [] ; while nops(a) < nmax do while bigprlen < 4 do bigpr := cat2(bigpr, p) ; bigprlen := bigprlen+A055642(p) ; p := nextprime(p) ; od: nodigs := bigprlen-4 ; a := [op(a), floor(bigpr/10^nodigs)] ; bigpr := bigpr mod (10^nodigs) ; bigprlen := bigprlen-4 ; od: RETURN(a) ; end: A136420(60) ; # R. J. Mathar, Apr 22 2008

Crossrefs

Sequence in context: A226267 A251295 A220626 * A132391 A346940 A134966

Adjacent sequences: A136417 A136418 A136419 * A136421 A136422 A136423

Keyword

nonn,base,easy

Author

N. J. A. Sloane, Apr 21 2008

Extensions

More terms from R. J. Mathar, Apr 22 2008

Status

approved