A091296 -id:A091296 - cp's OEIS frontend

A108637 Duplicate of A091296.

9, 15, 33, 35, 39, 51, 55, 57, 77, 91, 93, 95, 111, 115, 119, 133, 155, 159, 177, 319, 335

Offset: 1

dead

A030096 Primes whose digits are all odd.

3, 5, 7, 11, 13, 17, 19, 31, 37, 53, 59, 71, 73, 79, 97, 113, 131, 137, 139, 151, 157, 173, 179, 191, 193, 197, 199, 311, 313, 317, 331, 337, 353, 359, 373, 379, 397, 557, 571, 577, 593, 599, 719, 733, 739, 751, 757, 773, 797, 911, 919, 937, 953, 971, 977, 991

Offset: 1

Patrick De Geest

Seiichi Manyama, Table of n, a(n) for n = 1..10000 (terms 1..1000 from T. D. Noe)

Intersection of A000040 and A014261. Subsequence of A066640 and hence A014261. Subsequence of A038604. A091633 is a subsequence.

Cf. A076704 = odd-digit prime powers of prime numbers; A091296 = odd-digit semiprimes; A000040 = prime numbers; A001358 = semiprimes.

a030096 n = a030096_list !! (n-1)
a030096_list = filter f a000040_list where
   f x = odd d && (x < 10 || f x') where (x', d) = divMod x 10
-- Reinhard Zumkeller, Apr 07 2014, Jan 29 2013

[p: p in PrimesUpTo(1000) | forall{d: d in [0,2,4,6,8] | d notin Set(Intseq(p))}]; // Vincenzo Librandi, Apr 29 2019

Select[Prime[Range[500]],And@@OddQ[IntegerDigits[#]]&] (* Harvey P. Dale, Jan 28 2013 *)

is(n)=isprime(n) && #setintersect([0,2,4,6,8],Set(digits(n)))==0 \\ Charles R Greathouse IV, Feb 07 2017

Edited by N. J. A. Sloane at the suggestion of T. D. Noe and Jonathan Vos Post, Sep 15 2007

A107076 Odd-digit semiprimes, divisors of which are odd-digit primes.

Original entry on oeis.org

9, 15, 33, 35, 39, 51, 55, 57, 77, 91, 93, 95, 111, 119, 133, 155, 159, 177, 339, 355, 371, 393, 395, 511, 519, 537, 553, 573, 579, 591, 597, 755, 791, 917, 933, 939, 951, 955, 959, 973, 993, 995, 1119, 1137, 1191, 1337, 1351, 1379, 1393, 1555

Offset: 1

Zak Seidov, May 10 2005

Differs from A091296 in that A107076 doesn't contain terms 115=5*23,319=11*29,335=5*67,377=13*29, etc.

Cf. A000040, A001358, A076704, A091296, A030096.

A108636 Semiprimes with even digits.

Original entry on oeis.org

4, 6, 22, 26, 46, 62, 82, 86, 202, 206, 226, 262, 422, 446, 466, 482, 622, 626, 662, 802, 842, 862, 866, 886, 2026, 2042, 2062, 2066, 2206, 2246, 2402, 2426, 2446, 2462, 2602, 2606, 2642, 2846, 2866, 4006, 4022, 4222, 4226, 4262, 4282, 4286, 4406, 4426, 4442

Offset: 1

Zak Seidov, Jun 14 2005

Semiprimes with even digits are less numerous than those with odd digits, cf. A091296.

"Semiprimes with even digits are less numerous than those with odd digits" because (base 10): no integer after 10 can end in a 0 without being divisible by 2, 5 and at least one other prime; for a semiprime to end in 2, 4, 6, or 8 it must be divisible by 2 and a prime with almost as many digits as the semiprime (and primes get rarer as they get longer); no semiprime with all even digits after 22 can be a repdigit; and similar constraints. - Jonathan Vos Post, Nov 07 2005

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

Intersection of A001358 and A014263.

Cf. A091296.

f:= proc(n) local L,x,i;
  L:= convert(n,base,5);
  x:= 2*add(L[i]*10^(i-1),i=1..nops(L));
  if isprime(x/2) then x else NULL fi
end proc:
map(f, [$1..1000]); # Robert Israel, Oct 01 2024

Select[Range[6000], Plus@@Last/@FactorInteger[ # ]==2&&Union[EvenQ/@IntegerDigits[ # ]]=={True}&]

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A108637 Duplicate of A091296.

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A030096 Primes whose digits are all odd.

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A107076 Odd-digit semiprimes, divisors of which are odd-digit primes.

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A108636 Semiprimes with even digits.

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