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.

Showing 1-5 of 5 results.

A028374 Numbers that have only curved digits {0, 3, 6, 8, 9} or digits that are both curved and linear {2, 5}.

Original entry on oeis.org

0, 2, 3, 5, 6, 8, 9, 20, 22, 23, 25, 26, 28, 29, 30, 32, 33, 35, 36, 38, 39, 50, 52, 53, 55, 56, 58, 59, 60, 62, 63, 65, 66, 68, 69, 80, 82, 83, 85, 86, 88, 89, 90, 92, 93, 95, 96, 98, 99, 200, 202, 203, 205, 206, 208, 209, 220, 222, 223, 225, 226, 228, 229, 230, 232, 233
Offset: 1

Views

Author

Greg Heil (gheil(AT)scn.org), Dec 11 1999

Keywords

Comments

From Bernard Schott, Mar 26 2023: (Start)
Previous name was: "Curved numbers: numbers that have only curved digits (0, 2, 3, 5, 6, 8, 9)"; but in fact, the curved numbers form the sequence A072960.
This sequence allows all digits except for 1, 4 and 7. (End)

Examples

			From _K. D. Bajpai_, Sep 07 2014: (Start)
206 is in the sequence because it has only curved digits 2, 0 and 6.
208 is in the sequence because it has only curved digits 2, 0 and 8.
2035689 is the smallest number having all the curved digits.
(End)

Links

Crossrefs

Cf. A028373 (straight digits: 1, 4, 7), A072960 (curved digits: 0, 3, 6, 8, 9), A072961 (both straight and curved digits: 2, 5).
Combinations: A082741 (digits: 1, 2, 4, 5, 7), A361780 (digits: 0, 1, 3, 4, 6, 7, 8, 9).
Cf. A034470 (subsequence of primes).

Programs

  • Magma
    [n: n in [0..300] | Set(Intseq(n)) subset [0,2,3,5, 6,8,9] ]; // Vincenzo Librandi, Sep 19 2014
  • Maple
    N:= 3: S:= {0, 2, 3, 5, 6, 8, 9}: K:= S:
for j from 2 to N do
     K:= map(t -> seq(10*t+s, s=S), K);
         od:
print( K);  # K. D. Bajpai, Sep 07 2014
  • Mathematica
    f[n_] := Block[{id = IntegerDigits[n], curve = {0, 2, 3, 5, 6, 8, 9}}, If[ Union[ Join[id, curve]] == curve, True, False]]; Select[ Range[0, 240], f[ # ] & ]
Select[Range[0, 249], Union[DigitCount[#] * {1, 0, 0, 1, 0, 0, 1, 0, 0, 0}] == {0} &] (* Alonso del Arte, May 23 2014 *)
Select[Range[0,500],Intersection[IntegerDigits[#],{1,4,7}]=={}&] (* K. D. Bajpai, Sep 07 2014 *)
  • Python
    for n in range(10**3):
  s = str(n)
  if not (s.count('1') + s.count('4') + s.count('7')):
    print(n,end=', ') # Derek Orr, Sep 19 2014

Extensions

Corrected and extended by Rick L. Shepherd, May 21 2003
Offset corrected by Arkadiusz Wesolowski, Aug 15 2011
Definition clarified by Bernard Schott, Mar 25 2023

A079652 Prime numbers using only the curved digits 0, 3, 6, 8 and 9.

Original entry on oeis.org

3, 83, 89, 383, 389, 683, 809, 839, 863, 883, 983, 3083, 3089, 3389, 3803, 3833, 3863, 3889, 3989, 6089, 6389, 6689, 6803, 6833, 6863, 6869, 6883, 6899, 6983, 8009, 8039, 8069, 8089, 8093, 8363, 8369, 8389, 8609, 8663, 8669, 8689, 8693, 8699, 8803, 8839
Offset: 1

Views

Author

Shyam Sunder Gupta, Jan 23 2003

Keywords

Comments

Intersection of A000040 and A072960. - K. D. Bajpai, Sep 01 2014

Links

Crossrefs

Cf. A072960, A028374.
Cf. A034470.

Programs

  • Maple
    N:= 4: # to get all terms with up to N digits
Digs:= {0,3,6,8,9}:
A:= NULL:
for d from 1 to N do
  C:= combinat[cartprod]([Digs minus {0},Digs $(d-1)]);
  while not C[finished] do
    L:= C[nextvalue]();
    x:= add(L[i]*10^(d-i),i=1..d);
    if isprime(x) then A:= A,x fi
  od
od:
A; # Robert Israel, Aug 31 2014
  • Mathematica
    Select[ Range[8850], PrimeQ[ # ] && Union[ Join[ IntegerDigits[ # ], {0, 3, 6, 8, 9}]] == {0, 3, 6, 8, 9} &]
Select[Prime[Range[5000]], Intersection[IntegerDigits[#], {1, 2, 4, 5, 7}] == {} &] (* K. D. Bajpai, Sep 01 2014 *)
Select[FromDigits/@Tuples[{0,3,6,8,9},4],PrimeQ] (* Harvey P. Dale, Sep 05 2022 *)

A361822 Primes without {2, 5} as digits.

Original entry on oeis.org

3, 7, 11, 13, 17, 19, 31, 37, 41, 43, 47, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 131, 137, 139, 149, 163, 167, 173, 179, 181, 191, 193, 197, 199, 307, 311, 313, 317, 331, 337, 347, 349, 367, 373, 379, 383, 389, 397, 401, 409, 419, 431, 433, 439, 443, 449, 461, 463
Offset: 1

Views

Author

Bernard Schott, Mar 26 2023

Keywords

Comments

Subsequence of primes that are in A361780.

Links

Crossrefs

Intersection of A000040 and A361780.
Cf. A079651 (primes with {1, 4, 7}), A079652 (primes with {0, 3, 6, 8, 9}).
Cf. A247052 (primes with {1, 2, 4, 5, 7}), A034470 (primes with {0, 2, 3, 5, 6, 8, 9}).
Cf. A106116, A154761, A386320 - A386358 (primes without two decimal digits).
Cf. A385776.

Programs

  • Maple
    filter:= proc(n) convert(convert(n,base,10),set) intersect {2,5} = {} end proc:
select(filter, [seq(ithprime(i),i=1..1000)]); # Robert Israel, Mar 26 2023
  • Mathematica
    Select[Prime[Range[100]], AllTrue[IntegerDigits[#], ! MemberQ[{2, 5}, #1] &] &] (* Amiram Eldar, Mar 26 2023 *)
  • Python
    print(list(islice(primes_with("01346789"), 41))) # uses function/imports in A385776. Jason Bard, Jul 20 2025

A242756 Semiprimes having only the curved digits.

Original entry on oeis.org

6, 9, 22, 25, 26, 33, 35, 38, 39, 55, 58, 62, 65, 69, 82, 85, 86, 93, 95, 202, 203, 205, 206, 209, 226, 235, 253, 259, 262, 265, 289, 295, 298, 299, 302, 303, 305, 309, 323, 326, 329, 335, 339, 355, 358, 362, 365, 382, 386, 393, 395, 398, 502, 505, 526, 529, 533
Offset: 1

Views

Author

K. D. Bajpai, May 22 2014

Keywords

Comments

A curved-digit semiprime has only the curved digits, i.e., 0, 2, 3, 5, 6, 8 or 9.

Examples

			358 = 2 * 179 is semiprime having only the curved digits 3, 5 and 8. Hence appears in the sequence.
689 = 13 * 53 is semiprime having only the curved digits 6, 8 and 9. Hence appears in the sequence.

Links

Crossrefs

Cf. A028374, A001358, A034470.

Programs

  • Mathematica
    A242756 = {}; Do[a = PrimeOmega[n];If[a == 2 && Intersection[IntegerDigits[n], {1, 4, 7}] == {}, AppendTo[A242756, n]], {n, 1000}]; A242756
  • PARI
    s=[]; for(n=1, 600, if(bigomega(n)==2 && setintersect(vecsort(digits(n), , 8), [1,4,7])==[], s=concat(s, n))); s \\ Colin Barker, Jun 03 2014

A247016 Triangular numbers A000217 composed of only curved digits {0, 2, 3, 5, 6, 8, 9}.

Original entry on oeis.org

0, 3, 6, 28, 36, 55, 66, 253, 300, 325, 528, 595, 630, 666, 820, 903, 990, 2080, 2556, 2628, 2850, 2926, 3003, 3655, 3828, 5050, 5253, 5356, 5565, 5886, 5995, 6328, 6555, 6903, 8256, 8385, 20503, 22366, 23005, 23220, 23653, 25200, 26335, 26565, 28203, 28680, 28920
Offset: 1

Views

Author

K. D. Bajpai, Sep 09 2014

Keywords

Comments

Intersection of A000217 and A028374.

Examples

			a(10) = 528 is in the sequence because it is A000217(32) and composed of only curved digits 5, 2 and 8.
a(14) = 820 is in the sequence because it is A000217(40) and composed of only curved digits 8, 2 and 0.

Links

Crossrefs

Cf. A000217, A028374, A034470, A072960.

Programs

  • Mathematica
    A247016 = {}; Do[t = n*(n + 1)/2; If[Intersection[IntegerDigits[t], {1, 4, 7}] == {}, AppendTo[A247016, t]], {n,0, 500}]; A247016
Select[Accumulate[Range[0,300]],DigitCount[#,10,1]==DigitCount[#,10,4] == DigitCount[ #,10,7] == 0&] (* Harvey P. Dale, Apr 18 2019 *)
  • Python
    for n in range(2,10**3):
  s = str(int(n*(n-1)/2))
  if not (s.count('1') + s.count('4') + s.count('7')):
    print(int(s),end=', ') # Derek Orr, Sep 18 2014

Extensions

Added starting number 0 (suggested by D. Orr), added A-number in the name and examples. - Wolfdieter Lang, Oct 06 2014
Showing 1-5 of 5 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.