|
| |
|
|
A088604
|
|
a(n) = smallest prime in which n substrings containing the least significant digit are primes.
|
|
2
| |
|
|
2, 13, 113, 1223, 12113, 121283, 1237547, 12184967, 124536947, 1219861613, 12181833347, 121339693967, 1213536676883, 12673876537547, 121848768729173, 1275463876537547, 12429121339693967, 165678739293946997
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| a(n) need not contain a(n-1) as a substring.
We exclude substrings that begin with 0, so a(3) is not 103. - David Wasserman (wasserma(AT)spawar.navy.mil), Aug 12 2005
Agrees with A127891 for 24 terms, but A127891 ends there while this sequence continues. - Ray Chandler (rayjchandler(AT)sbcglobal.net), Mar 13 2007
|
|
|
EXAMPLE
| a(4) = 1223 in which the four substrings containing the LSD (3,23,223,1223) are primes.
|
|
|
PROG
| (PARI) f(n, d, digs, spare) = local(p, r, found); if (!d, return(n)); found = 0; for (i = 0, 9, p = n + i*10^digs; if ((i && isprime(p)) || spare, r = f(p, d - 1, digs + 1, spare - 1 + (i && isprime(p)))); if (r && (r < found || !found), found = r)); found; a(n) = local(i, r); i = 0; while (1, r = f(0, n + i, 0, i); if (r, return(r), i++)); (Wasserman)
|
|
|
CROSSREFS
| Cf. A088603, A127891.
Sequence in context: A046813 A096497 * A127891 A110369 A000180 A192460
Adjacent sequences: A088601 A088602 A088603 * A088605 A088606 A088607
|
|
|
KEYWORD
| base,nonn
|
|
|
AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Oct 15 2003
|
|
|
EXTENSIONS
| More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Aug 12 2005
|
| |
|
|
