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A136420
List of primes with digits grouped into clumps of four. Leading zeros are not printed.
1
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.
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
KEYWORD
nonn,base,easy
AUTHOR
N. J. A. Sloane, Apr 21 2008
EXTENSIONS
More terms from R. J. Mathar, Apr 22 2008
STATUS
approved