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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A054476 Numbers not divisible by any of their digits when written in base 5.

Original entry on oeis.org

13, 17, 19, 23, 53, 65, 67, 73, 77, 79, 85, 89, 94, 95, 97, 98, 103, 113, 115, 118, 119, 253, 263, 265, 269, 313, 317, 319, 323, 325, 329, 335, 337, 343, 347, 349, 353, 365, 367, 373, 377, 379, 385, 389, 394, 395, 397, 398, 425, 427, 437, 439, 443, 445, 449
Offset: 1

Views

Author

Henry Bottomley, May 12 2000

Keywords

Crossrefs

Programs

  • PARI
    is(n)=my(d=Set(digits(n,5))); for(i=if(d[1],1,2),#d, if(n%d[i]==0, return(0))); 1 \\ Charles R Greathouse IV, Feb 23 2017

A082947 Palindromes not divisible by any of their digits.

Original entry on oeis.org

323, 343, 353, 373, 383, 434, 454, 474, 494, 646, 656, 676, 686, 727, 737, 747, 757, 767, 787, 797, 838, 858, 868, 878, 898, 929, 949, 959, 969, 979, 989, 3223, 3443, 3553, 3883, 4334, 4554, 4994, 6446, 6556, 6886, 7227, 7337, 7447, 7557, 7667, 7887, 7997
Offset: 1

Views

Author

Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 08 2003

Keywords

Comments

Intersection of A002113 and A038772. - Michel Marcus, Mar 07 2015

Examples

			969 is a member of the sequence since it is neither divisible by 9 nor 6 but 8778 is not since it is divisible by 7.
		

References

Crossrefs

Cf. A002113 (palindromes in base 10), A038772 (numbers not divisible by any of their digits).

Programs

A147963 a(n) = number of n-digit numbers not divisible by any of their digits.

Original entry on oeis.org

0, 31, 244, 2012, 16831, 142224, 1212521, 10412937, 89964007, 781192156, 6812648578, 59632654665, 523659800584, 4611408084221, 40708677441051, 360148330033068, 3192319968308509, 28344332639409466, 252044515540416543, 2244223537121190033, 20006367211775121313
Offset: 1

Views

Author

Zak Seidov, Nov 17 2008

Keywords

Comments

Numbers ending in 0 are ignored.

Crossrefs

Cf. A038772 Numbers not divisible by any of their digits.

Programs

  • Mathematica
    a[n_] := (c = 0; Do[id = IntegerDigits[i]; Le = Length[id]; pr = Product[If[id[[k]] > 0, Mod[i, id[[k]]], 1], {k, Le}]; If[Mod[i, 10]*pr > 0,(*Print[n];*)c++ ], {i, 10^(n - 1), 10^n - 1}]; c); a[1] = 0; Table[a[m], {m, 8}]

Extensions

a(10)-a(11) from Sean A. Irvine, Nov 11 2010
a(12) from Donovan Johnson, Nov 14 2010
a(13)-a(21) from Hiroaki Yamanouchi, Aug 31 2014

A176659 Partial sums of A038770.

Original entry on oeis.org

1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 105, 120, 136, 153, 171, 190, 210, 231, 253, 277, 302, 328, 356, 386, 417, 449, 482, 517, 553, 592, 632, 673, 715, 759, 804, 852, 902, 953, 1005, 1060, 1120, 1181, 1243, 1306, 1370, 1435, 1501, 1571, 1642
Offset: 1

Views

Author

Jonathan Vos Post, Apr 23 2010

Keywords

Comments

Partial sums of numbers divisible by at least one of their digits. Identical to triangular numbers A000217 until a(23), then differs, because 23 is the smallest natural number in the complement of A038770 (A038772, i.e., not divisible by at least one of its digits). Hence this partial sum is the triangular numbers minus the partial sums of A038772, properly offset. The subsequence of primes (of course 3 is the largest prime triangular number) in the partial sum begins: 3, 277, 449, 673, 953, 1181, 1571, 1789, 2027. What are the equivalents in bases other than 10?

Examples

			a(23) = 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20 + 21 + 22 + 24 = 277 is prime.
		

Crossrefs

Programs

  • Mathematica
    Accumulate[Select[Range[110],MemberQ[Divisible[#,Cases[ IntegerDigits[ #], Except[ 0]]], True]&]] (* Harvey P. Dale, May 11 2017 *)

Formula

a(n) = Sum_{i=1..n} A038770(i).

A188454 Numbers n whose decimal digits are distinct and no digit divides n.

Original entry on oeis.org

23, 27, 29, 34, 37, 38, 43, 46, 47, 49, 53, 54, 56, 57, 58, 59, 67, 68, 69, 73, 74, 76, 78, 79, 83, 86, 87, 89, 94, 97, 98, 203, 207, 209, 239, 247, 249, 253, 257, 259, 263, 267, 269, 283, 289, 293, 307, 308, 329, 346, 347, 349, 356, 358, 359, 367, 370, 374
Offset: 1

Views

Author

Andy Edwards, Mar 31 2011

Keywords

Comments

These may not contain 1 or have a 2 or 5 as the last digit. They include prime numbers not containing the digit 1 and composites with a smallest prime factor > 10 and obeying the other constraints (e.g. the largest case is 987654203 = 31*31859813).
The first even case is 34. The first consecutive pair is {37, 38}. {56,57,58,59} is a consecutive quadruple which is the maximal size for such a subset.
There are 202623 terms in this sequence. - Nathaniel Johnston, May 19 2011

Crossrefs

Programs

  • Mathematica
    dddQ[n_]:=Module[{dcn=DigitCount[n]},Max[dcn]==1&&First[dcn]==0 && Union[ Divisible[n,Select[IntegerDigits[n],#!=0&]]]=={False}]; Select[Range[ 400],dddQ] (* Harvey P. Dale, May 01 2012 *)

A331342 Lexicographically earliest sequence of distinct terms a(n) indivisible by all of their digits that become divisible by all of their digits when a(n+1) is added to a(n).

Original entry on oeis.org

23, 43, 34, 54, 57, 58, 53, 46, 69, 59, 29, 37, 74, 38, 73, 49, 79, 47, 68, 56, 76, 86, 89, 223, 389, 247, 377, 67, 257, 367, 269, 97, 27, 397, 227, 439, 233, 379, 293, 343, 323, 289, 347, 277, 359, 253, 83, 229, 259, 353, 283, 329, 337, 87, 249, 239, 94, 338, 334, 78, 346, 98, 457, 479, 634, 477, 638
Offset: 1

Views

Author

Eric Angelini and Jean-Marc Falcoz, Jan 14 2020

Keywords

Comments

Is this sequence a reordering of A038772?

Examples

			a(1) = 23 is not divisible by 2 and not divisible by 3. When a(2) = 43 is added to a(1) = 23, the result (66) is divisible by all its digits.
a(2) = 43 is not divisible by 4 and not divisible by 3. When a(3) = 34 is added to a(2) = 43, the result (77) is divisible by all its digits.
a(3) = 34 is not divisible by 3 and not divisible by 4. When a(4) = 54 is added to a(3) = 34, the result (88) is divisible by all its digits.
a(4) = 54 is not divisible by 5 and not divisible by 4. When a(5) = 57 is added to a(4) = 54, the result (111) is divisible by all its digits.
a(5) = 57 is not divisible by 5 and not divisible by 7. When a(6) = 58 is added to a(5) = 57, the result (115) is divisible by all its digits....
		

Crossrefs

A342844 Composite numbers not divisible by any of their nonzero digits.

Original entry on oeis.org

27, 34, 38, 46, 49, 54, 56, 57, 58, 68, 69, 74, 76, 78, 86, 87, 94, 98, 203, 207, 209, 247, 249, 253, 259, 267, 289, 299, 308, 323, 329, 334, 338, 343, 346, 356, 358, 370, 374, 376, 377, 380, 386, 388, 394, 398, 403, 406, 407, 429, 430, 434, 437, 446, 447, 454
Offset: 1

Views

Author

John Bibby, Mar 24 2021

Keywords

Crossrefs

Programs

  • Maple
    q:= n-> not isprime(n) and andmap(d-> irem(n, d)>0,
            {convert(n, base, 10)[]} minus {0}):
    select(q, [$1..500])[];  # Alois P. Heinz, Apr 01 2021
  • Mathematica
    Select[Range@500,!PrimeQ@#&&Mod[#,DeleteCases[IntegerDigits@#,0]]~FreeQ~0&] (* Giorgos Kalogeropoulos, Apr 01 2021 *)
    Select[Range[500],CompositeQ[#]&&NoneTrue[#/(IntegerDigits[#]/.(0-> Nothing)),IntegerQ]&] (* Harvey P. Dale, Dec 28 2021 *)
  • PARI
    isok(n)={if(isprime(n), 0, my(v=digits(n)); for(i=1, #v, if(v[i]<>0 && n%v[i]==0, return(0))); 1)} \\ Andrew Howroyd, Mar 25 2021
    
  • Python
    from sympy import isprime
    def ok(n): return not isprime(n) and all(n%int(d) for d in str(n) if d!='0')
    print(list(filter(ok, range(4, 455)))) # Michael S. Branicky, Apr 01 2021

A054475 Numbers not divisible by any of their digits when written in base 4.

Original entry on oeis.org

11, 35, 43, 47, 59, 131, 139, 143, 163, 175, 179, 187, 191, 203, 227, 235, 239, 251, 515, 523, 527, 547, 559, 563, 571, 575, 643, 655, 683, 691, 703, 707, 715, 719, 739, 751, 755, 763, 767, 779, 803, 811, 815, 827, 899, 907, 911, 931, 943, 947, 955, 959
Offset: 1

Views

Author

Henry Bottomley, May 12 2000

Keywords

Crossrefs

A054478 Numbers not divisible by any of their digits when written in base 6.

Original entry on oeis.org

17, 22, 23, 29, 34, 77, 89, 101, 107, 113, 130, 131, 137, 142, 143, 149, 161, 166, 167, 173, 174, 178, 179, 197, 202, 203, 209, 214, 437, 449, 461, 467, 509, 521, 527, 533, 539, 557, 563, 569, 581, 593, 599, 611, 617, 629, 641, 647, 653, 670, 671, 677, 682
Offset: 1

Views

Author

Henry Bottomley, May 12 2000

Keywords

Crossrefs

A054484 Numbers not divisible by any of their digits when written in base 7.

Original entry on oeis.org

17, 19, 23, 25, 26, 31, 33, 34, 37, 38, 39, 41, 46, 47, 101, 103, 115, 117, 119, 121, 125, 131, 133, 137, 139, 143, 149, 151, 152, 161, 163, 167, 173, 175, 178, 179, 181, 182, 187, 188, 191, 193, 194, 199, 201, 202, 217, 221, 223, 227, 229, 230, 231, 233, 237
Offset: 1

Views

Author

Henry Bottomley, May 12 2000

Keywords

Crossrefs

Previous Showing 21-30 of 33 results. Next