A132285 -id:A132285 - cp's OEIS frontend

A132286 Odd palindromes with an even number of digits divided by 11.

1, 3, 5, 7, 9, 91, 101, 111, 121, 131, 141, 151, 161, 171, 181, 273, 283, 293, 303, 313, 323, 333, 343, 353, 363, 455, 465, 475, 485, 495, 505, 515, 525, 535, 545, 637, 647, 657, 667, 677, 687, 697, 707, 717, 727, 819, 829, 839, 849, 859, 869, 879, 889, 899

Offset: 1

Artur Jasinski, Aug 16 2007

Cf. A132285.

lista(nn) = {for (n=1, nn, if (isA132285(n), print1(n/11, ", ");););} \\ Michel Marcus, Nov 05 2013

a(n) = A132285(n)/11.

A132288 Odd palindromes which are semiprimes with an even number of digits.

Original entry on oeis.org

33, 55, 77, 1111, 1441, 1661, 1991, 3113, 3223, 3443, 3883, 7117, 7447, 7997, 9119, 9229, 9449, 100001, 103301, 104401, 107701, 113311, 115511, 116611, 124421, 125521, 130031, 136631, 139931, 146641, 152251, 157751, 160061, 163361, 164461, 169961, 170071

Offset: 1

Artur Jasinski, Aug 16 2007

One of the divisors is 11 and the other is A132287(n).

Robert Israel, Table of n, a(n) for n = 1..10000

Intersection of A132285 and A001358.

Cf. A132286, A132287.

rev:= proc(n) local L,i; L:= convert(n,base,10); add(L[-i]*10^(i-1),i=1..nops(L)) end proc:
f:= proc(m) local A,i,j,k;
  select(t -> isprime(t/11), [seq(seq(10^(m-1)*i + 10^(m/2)*j + rev(10^(m/2-1)*i+j),j=0 .. 10^(m/2-1)-1),i=[1,3,5,7, 9])])
end proc:
seq(op(f(m)),m=2..6,2); # Robert Israel, Jan 05 2025

lista(nn) = {for(n=1, nn, if (ismo(n) && (bigomega(n) == 2), print1(n, ", ");););} \\ where ismo is isok in A132285 \\ Michel Marcus, Nov 05 2013

a(n) = 11*A132287(n).

More terms from Michel Marcus, Nov 05 2013

Name edited by Robert Israel, Jan 05 2025

A132287 Primes in A132286.

Original entry on oeis.org

3, 5, 7, 101, 131, 151, 181, 283, 293, 313, 353, 647, 677, 727, 829, 839, 859, 9091, 9391, 9491, 9791, 10301, 10501, 10601, 11311, 11411, 11821, 12421, 12721, 13331, 13841, 14341, 14551, 14851, 14951, 15451, 15461, 15661, 15761, 16061, 16361, 16871, 17581

Offset: 1

Artur Jasinski, Aug 16 2007

Cf. A132285, A132286.

lista(nn) = {for(n=1, nn, if (isA132285(n) && isprime(p=n/11), print1(p, ", ");););} \\ Michel Marcus, Nov 05 2013

More terms from Michel Marcus, Nov 05 2013

cp's OEIS Frontend

A132286 Odd palindromes with an even number of digits divided by 11.

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A132288 Odd palindromes which are semiprimes with an even number of digits.

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Maple

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A132287 Primes in A132286.

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