A062332 Primes starting and ending with 1.

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

Harry J. Smith, Table of n, a(n) for n = 1..1000

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).

Cf. A010051, A017281, A131835, A000030.

Sequence in context: A316604 A208362 A159613 * A222723 A088281 A068685

Adjacent sequences: A062329 A062330 A062331 * A062333 A062334 A062335

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