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A062332
Primes starting and ending with 1.
9
11, 101, 131, 151, 181, 191, 1021, 1031, 1051, 1061, 1091, 1151, 1171, 1181, 1201, 1231, 1291, 1301, 1321, 1361, 1381, 1451, 1471, 1481, 1511, 1531, 1571, 1601, 1621, 1721, 1741, 1801, 1811, 1831, 1861, 1871, 1901, 1931, 1951, 10061, 10091, 10111, 10141
OFFSET
1,1
COMMENTS
Complement of A208261 (nonprime numbers with all divisors starting and ending with digit 1) with respect to A208262 (numbers with all divisors starting and ending with digit 1). - Jaroslav Krizek, Mar 04 2012
Intersection of A030430 and A045707. - Michel Marcus, Jun 08 2013
LINKS
FORMULA
A010051(a(n)) * A000030(a(n)) * (a(n) mod 10) = 1. - Reinhard Zumkeller, Jul 16 2014
EXAMPLE
102701 is a member as it is a prime and the first and the last digits are both 1.
MATHEMATICA
fl1Q[n_]:=Module[{idn=IntegerDigits[n]}, First[idn]==Last[idn]==1]; Select[ Prime[Range[1300]], fl1Q] (* Harvey P. Dale, Apr 30 2012 *)
PROG
(PARI) { n=-1; t=log(10); forprime (p=2, 5*10^5, if ((p-10*(p\10)) == 1 && (p\10^(log(p)\t)) == 1, write("b062332.txt", n++, " ", p); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 05 2009
(Haskell)
a062332 n = a062332_list !! (n-1)
a062332_list = filter ((== 1) . a010051') a208259_list
-- Reinhard Zumkeller, Jul 16 2014
CROSSREFS
Cf. A208259 (Numbers starting and ending with digit 1).
Sequence in context: A316604 A208362 A159613 * A222723 A088281 A068685
KEYWORD
nonn,base,easy
AUTHOR
Amarnath Murthy, Jun 21 2001
EXTENSIONS
Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jun 29 2001
Missing term a(36)=1901 added by Harry J. Smith, Aug 05 2009
STATUS
approved