cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A092624 Numbers with exactly two prime digits.

Original entry on oeis.org

22, 23, 25, 27, 32, 33, 35, 37, 52, 53, 55, 57, 72, 73, 75, 77, 122, 123, 125, 127, 132, 133, 135, 137, 152, 153, 155, 157, 172, 173, 175, 177, 202, 203, 205, 207, 212, 213, 215, 217, 220, 221, 224, 226, 228, 229, 230, 231, 234, 236, 238, 239, 242, 243, 245
Offset: 1

Views

Author

Jani Melik, Apr 11 2004

Keywords

Comments

A193238(a(n))=2; subsequence of A118950. [Reinhard Zumkeller, Jul 19 2011]

Examples

			25 has two prime digits, 2 and 5;
207 has two prime digits, 2 and 7.
		

Crossrefs

Programs

  • Haskell
    import Data.List (elemIndices)
    a092624 n = a092624_list !! (n-1)
    a092624_list = elemIndices 2 a193238_list
    -- Reinhard Zumkeller, Jul 19 2011
  • Maple
    stev_sez:=proc(n) local i, tren, st, ans, anstren; ans:=[ ]: anstren:=[ ]: tren:=n: for i while (tren>0) do st:=round( 10*frac(tren/10) ): ans:=[ op(ans), st ]: tren:=trunc(tren/10): end do; for i from nops(ans) to 1 by -1 do anstren:=[ op(anstren), op(i,ans) ]; od; RETURN(anstren); end: ts_stpf:=proc(n) local i, stpf, ans; ans:=stev_sez(n): stpf:=0: for i from 1 to nops(ans) do if (isprime(op(i,ans))='true') then stpf:=stpf+1; # number of prime digits fi od; RETURN(stpf) end: ts_pr_nd:=proc(n) local i, stpf, ans, ans1, tren; ans:=[ ]: stpf:=0: tren:=1: for i from 1 to n do if ( ts_stpf(i) = 2) then ans:=[ op(ans), i ]: tren:=tren+1; fi od; RETURN(ans) end: ts_pr_nd(500);
  • Mathematica
    Select[Range[300],Count[IntegerDigits[#],?PrimeQ]==2&] (* _Harvey P. Dale, Apr 20 2025 *)

A092625 Numbers with exactly three prime digits.

Original entry on oeis.org

222, 223, 225, 227, 232, 233, 235, 237, 252, 253, 255, 257, 272, 273, 275, 277, 322, 323, 325, 327, 332, 333, 335, 337, 352, 353, 355, 357, 372, 373, 375, 377, 522, 523, 525, 527, 532, 533, 535, 537, 552, 553, 555, 557, 572, 573, 575, 577, 722, 723, 725
Offset: 1

Views

Author

Jani Melik, Apr 11 2004

Keywords

Comments

It is the same as A046034 from two digit numbers from 22 up to four digit numbers from 1222.
A193238(a(n))=3; subsequence of A118950. [Reinhard Zumkeller, Jul 19 2011]

Examples

			222 has three prime digits, three times 2;
1235 has three prime digits, 2, 3 and 5.
		

Crossrefs

Programs

  • Haskell
    import Data.List (elemIndices)
    a092625 n = a092625_list !! (n-1)
    a092625_list = elemIndices 3 a193238_list
    -- Reinhard Zumkeller, Jul 19 2011
  • Maple
    stev_sez:=proc(n) local i, tren, st, ans, anstren; ans:=[ ]: anstren:=[ ]: tren:=n: for i while (tren>0) do st:=round( 10*frac(tren/10) ): ans:=[ op(ans), st ]: tren:=trunc(tren/10): end do; for i from nops(ans) to 1 by -1 do anstren:=[ op(anstren), op(i,ans) ]; od; RETURN(anstren); end: ts_stpf:=proc(n) local i, stpf, ans; ans:=stev_sez(n): stpf:=0: for i from 1 to nops(ans) do if (isprime(op(i,ans))='true') then stpf:=stpf+1; # number of prime digits fi od; RETURN(stpf) end: ts_pr_nt:=proc(n) local i, stpf, ans, ans1, tren; ans:=[ ]: stpf:=0: tren:=1: for i from 1 to n do if ( ts_stpf(i) = 3) then ans:=[ op(ans), i ]: tren:=tren+1; fi od; RETURN(ans) end: ts_pr_nt(2000);
  • Mathematica
    Select[Range[800],Total[Boole[PrimeQ[IntegerDigits[#]]]]==3&] (* Harvey P. Dale, Dec 31 2023 *)

A276729 Number of nonprime digits in the decimal expansion of n.

Original entry on oeis.org

1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 2, 2, 1, 1, 2, 1, 2, 1, 2, 2, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 2, 2, 1, 1, 2, 1, 2, 1, 2, 2, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 2, 2, 1, 1, 2, 1, 2, 1, 2, 2, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 2, 2, 1, 1, 2, 1, 2, 1, 2, 2, 2
Offset: 0

Views

Author

M. F. Hasler, Sep 16 2016

Keywords

Crossrefs

Cf. A011557 (integers that give records).

Programs

  • Maple
    f:= proc(n) local t; option remember;
      t:= n mod 10;
    procname((n-t)/10) + `if`(member(t,[2,3,5,7]),0,1)
    end proc:
    f(0):= 0:
    1,seq(f(i),i=1..100); # Robert Israel, Feb 27 2019
  • PARI
    a(n)=#select(t->!isprime(t),digits(n))

Formula

a(n) = A055642(n) - A193238(n).
a(A046034(n)) = 0. - Gordon Atkinson, Sep 06 2019

A085558 Numbers that have more nonprime digits than prime digits.

Original entry on oeis.org

0, 1, 4, 6, 8, 9, 10, 11, 14, 16, 18, 19, 40, 41, 44, 46, 48, 49, 60, 61, 64, 66, 68, 69, 80, 81, 84, 86, 88, 89, 90, 91, 94, 96, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 124, 126, 128, 129, 130
Offset: 1

Views

Author

Jason Earls, Jul 04 2003

Keywords

Crossrefs

Cf. A084984.

Programs

  • Mathematica
    pdnpdQ[n_]:=With[{idn=IntegerDigits[n]},Count[idn,?(PrimeQ[#]&)]<Count[idn,?(!PrimeQ[ #]&)]]; Select[Range[0,150],pdnpdQ] (* Harvey P. Dale, Dec 19 2023 *)
  • PARI
    isok(n) = {my(d = if (n, digits(n), [0]), nbp = #select(x->isprime(x), d)); 2*nbp < #d;} \\ Michel Marcus, Feb 28 2019

Extensions

0 added by Arkadiusz Wesolowski, Jul 11 2011

A084988 Numbers made with nonprime digits such that the sum of the digits is also not prime.

Original entry on oeis.org

1, 4, 6, 8, 9, 10, 18, 19, 40, 44, 46, 48, 60, 64, 66, 68, 69, 80, 81, 84, 86, 88, 90, 91, 96, 99, 100, 108, 109, 114, 116, 118, 141, 144, 149, 161, 168, 169, 180, 181, 186, 189, 190, 194, 196, 198
Offset: 1

Views

Author

Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 27 2003

Keywords

Examples

			E.g. 46 is not prime and 4+6 =10 is also not prime.
		

Crossrefs

Cf. A084984.

Programs

  • Mathematica
    Select[Rest[FromDigits/@Tuples[{0,1,4,6,8,9},3]],!PrimeQ[ Total[ IntegerDigits[ #]]]&] (* Harvey P. Dale, Jul 20 2017 *)

A155547 a(n) = prime(n) without prime digits in n.

Original entry on oeis.org

2, 7, 13, 19, 23, 29, 31, 43, 53, 61, 67, 173, 179, 193, 199, 223, 227, 281, 283, 311, 317, 337, 347, 409, 419, 433, 443, 457, 461, 463, 467, 491, 503, 521, 523, 541, 547, 569, 577, 593, 599, 601, 607, 619, 641, 647, 653, 809, 811, 827, 839, 857, 859, 941, 947
Offset: 1

Views

Author

Juri-Stepan Gerasimov, Jan 24 2009

Keywords

Comments

Prime digit = 2, 3, 5 or 7.

Crossrefs

Programs

  • Maple
    isA084984 := proc(n) local dgs ; dgs := convert(convert(n,base,10),set) ; if dgs intersect {2,3,5,7} <> {} then false; else true; fi; end: A084984 := proc(n) option remember ; local a ; if n = 1 then 1; else for a from procname(n-1)+1 do if isA084984(a) then RETURN(a) ; fi; od; fi; end: A155547 := proc(n) ithprime(A084984(n)) ; end: for n from 1 to 80 do printf("%d,",A155547(n)) ; od: # R. J. Mathar, Jan 25 2009
  • Mathematica
    Prime[#]&/@Select[Range[200],NoneTrue[IntegerDigits[#],PrimeQ]&] (* Harvey P. Dale, Jan 28 2024 *)

Formula

a(n) = A000040(A084984(n)). - R. J. Mathar, Jan 25 2009

A365471 Numbers whose digits are not all primes.

Original entry on oeis.org

0, 1, 4, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 24, 26, 28, 29, 30, 31, 34, 36, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 54, 56, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 74, 76, 78, 79, 80, 81, 82, 83, 84, 85, 86
Offset: 1

Views

Author

James C. McMahon, Sep 11 2023

Keywords

Comments

Complement of A046034.
Union of A084984 and A365589.

Crossrefs

Programs

  • Mathematica
    a[n_Integer?NonNegative] := Select[Range[0, n], Not[AllTrue[MemberQ[{2, 3, 5, 7}, #] & /@ IntegerDigits@#, Identity]] &]; a[86] (* Robert P. P. McKone, Sep 13 2023 *)
    Select[Range[0,100],AnyTrue[IntegerDigits[#],!PrimeQ[#]&]&] (* Harvey P. Dale, Dec 22 2023 *)

A365472 Numbers whose digits are either all primes or all nonprimes.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 14, 16, 18, 19, 22, 23, 25, 27, 32, 33, 35, 37, 40, 41, 44, 46, 48, 49, 52, 53, 55, 57, 60, 61, 64, 66, 68, 69, 72, 73, 75, 77, 80, 81, 84, 86, 88, 89, 90, 91, 94, 96, 98, 99, 100, 101, 104, 106, 108, 109, 110, 111, 114
Offset: 1

Views

Author

James C. McMahon, Sep 11 2023

Keywords

Comments

Complement of A365589.
Union of A046034 and A084984.

Crossrefs

Programs

  • Mathematica
    a[n_Integer?NonNegative] := Select[Range[0, n], Module[{digits, primeDigits}, digits = IntegerDigits[#]; primeDigits = MemberQ[{2, 3, 5, 7}, #] & /@ digits; AllTrue[primeDigits, Identity] || AllTrue[primeDigits, Not]] &]; a[114] (* Robert P. P. McKone, Sep 13 2023 *)

A380490 Replace prime digits of n by 0's.

Original entry on oeis.org

1, 0, 0, 4, 0, 6, 0, 8, 9, 10, 11, 10, 10, 14, 10, 16, 10, 18, 19, 0, 1, 0, 0, 4, 0, 6, 0, 8, 9, 0, 1, 0, 0, 4, 0, 6, 0, 8, 9, 40, 41, 40, 40, 44, 40, 46, 40, 48, 49, 0, 1, 0, 0, 4, 0, 6, 0, 8, 9, 60, 61, 60, 60, 64, 60, 66, 60, 68, 69, 0, 1, 0, 0, 4, 0, 6, 0, 8, 9, 80, 81, 80
Offset: 1

Views

Author

Ctibor O. Zizka, Jan 25 2025

Keywords

Examples

			n = 7: 7 --> 0, thus a(7) = 0.
n = 26: 26 --> 06, thus a(26) = 6.
n = 472: 472 --> 400, thus a(472) = 400.
		

Crossrefs

Programs

  • Maple
    f:= proc(n) local L,i;
      L:= convert(n,base,10);
      add(`if`(isprime(L[i]),0,L[i]) * 10^(i-1),i=1..nops(L))
    end proc:
    map(f, [$1..100]); # Robert Israel, May 18 2025
  • Mathematica
    a[n_] := FromDigits[IntegerDigits[n] /. ?PrimeQ -> 0]; Array[a, 100] (* _Amiram Eldar, Jan 25 2025 *)
  • Python
    def a(n): return int(str(n).translate({50:48,51:48,53:48,55:48}))
    print([a(n) for n in range(1, 83)]) # Michael S. Branicky, Jan 25 2025

Formula

a(A084984(n)) = A084984(n).
a(A046034(n)) = 0.

A383934 Composite numbers that contain only nonprime digits and whose prime factors contain only nonprime digits.

Original entry on oeis.org

1111, 1199, 1681, 1691, 1919, 1991, 4141, 4411, 4469, 4499, 4609, 4961, 6109, 6161, 6611, 6649, 6809, 8899, 8989, 9089, 9481, 9691, 10109, 10901, 11009, 11041, 11099, 11419, 11881, 14641, 14801, 16109, 16441, 16489, 16999, 18409, 18491, 18601, 18689
Offset: 1

Views

Author

Scott R. Shannon, Aug 17 2025

Keywords

Examples

			10109 is a term as 10109 = 11 * 919, and both the number and its prime factors only contain nonprime digits.
		

Crossrefs

Programs

  • Mathematica
    Select[Select[Range[20000], And[CompositeQ[#], NoneTrue[IntegerDigits[#], PrimeQ]] &], NoneTrue[Flatten[IntegerDigits /@ FactorInteger[#][[All, 1]] ], PrimeQ] &] (* Michael De Vlieger, Aug 23 2025 *)
Previous Showing 21-30 of 32 results. Next