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 1-10 of 27 results. Next

A244918 Primes p where the digital sum is equal to 68.

Original entry on oeis.org

59999999, 69999899, 69999989, 78998999, 88989899, 88999979, 89699999, 89799989, 89989799, 89989979, 89997899, 89997989, 89999699, 89999969, 97889999, 98699999, 98879999, 98899799, 98979989, 98988899, 98989889, 98997989, 98998979, 98999969
Offset: 1

Views

Author

Vincenzo Librandi, Jul 08 2014

Keywords

Examples

			69999899 is a prime with sum of the digits = 68, hence belongs to the sequence.
		

Crossrefs

Cf. Primes p where the digital sum is equal to k: 2, 11 and 101 for k=2; A062339 (k=4), A062341 (k=5), A062337 (k=7), A062343 (k=8), A107579 (k=10), A106754 (k=11), A106755 (k=13), A106756 (k=14), A106757 (k=16), A106758 (k=17), A106759 (k=19), A106760 (k=20), A106761 (k=22), A106762 (k=23), A106763 (k=25), A106764 (k=26), A048517 (k=28), A106766 (k=29), A106767 (k=31), A106768 (k=32), A106769 (k=34), A106770 (k=35), A106771 (k=37), A106772 (k=38), A106773 (k=40), A106774 (k=41), A106775 (k=43), A106776 (k=44), A106777 (k=46), A106778 (k=47), A106779 (k=49), A106780 (k=50), A106781 (k=52), A106782 (k=53), A106783 (k=55), A106784 (k=56), A106785 (k=58), A106786 (k=59), A106787 (k=61), A107617 (k=62), A107618 (k=64), A107619 (k=65), A106807 (k=67), this sequence (k=68), A181321 (k=70).

Programs

  • Magma
    [p: p in PrimesUpTo(100000000) | &+Intseq(p) eq 68];
    
  • Mathematica
    Select[Prime[Range[10000000]], Total[IntegerDigits[#]]==68 &]
  • Python
    # see code in A107579: the same code can be used to produce this sequence, by giving the initial term p = 6*10**7-1, for digit sum 68. - M. F. Hasler, Mar 16 2022

A001101 Moran numbers: k such that k/(sum of digits of k) is prime.

Original entry on oeis.org

18, 21, 27, 42, 45, 63, 84, 111, 114, 117, 133, 152, 153, 156, 171, 190, 195, 198, 201, 207, 209, 222, 228, 247, 261, 266, 285, 333, 370, 372, 399, 402, 407, 423, 444, 465, 481, 511, 516, 518, 531, 555, 558, 592, 603
Offset: 1

Views

Author

Bill Moran (moran1(AT)llnl.gov)

Keywords

Comments

Witno conjectures that a(n) ~ c*n log(n)^2 for some c. - Charles R Greathouse IV, Jul 26 2011

References

  • Bill Moran, Problem 2074: The Moran Numbers, J. Rec. Math., Vol. 25 No. 3, pp. 215, 1993.

Crossrefs

Subsequence of A005349, Niven (or Harshad) numbers.

Programs

  • Haskell
    import Data.List (findIndices)
    a001101 n = a001101_list !! (n-1)
    a001101_list = map succ $ findIndices p [1..] where
       p n = m == 0 && a010051 n' == 1 where
          (n', m) = divMod n (a007953 n)
    -- Reinhard Zumkeller, Jun 16 2011
    
  • Maple
    filter:= proc(n) local q;
      q:= n/convert(convert(n,base,10),`+`);
      q::integer and isprime(q)
    end proc:
    select(filter, [$1..1000]); # Robert Israel, May 13 2025
  • Mathematica
    Select[Range[700], PrimeQ[ # / Total[IntegerDigits[#]]]&] (* Jean-François Alcover, Nov 30 2011 *)
  • PARI
    is(n)=(k->denominator(k)==1&&isprime(k))(n/sumdigits(n)) \\ Charles R Greathouse IV, Jan 10 2014
    
  • Python
    from sympy import isprime
    def ok(n): s = sum(map(int, str(n))); return s and n%s==0 and isprime(n//s)
    print([k for k in range(604) if ok(k)]) # Michael S. Branicky, Mar 28 2022

Extensions

Name corrected by Charles R Greathouse IV, Jan 10 2014

A062341 Primes whose sum of digits is 5.

Original entry on oeis.org

5, 23, 41, 113, 131, 311, 401, 1013, 1031, 1103, 1301, 2003, 2111, 3011, 4001, 10103, 10211, 10301, 11003, 12011, 12101, 13001, 20021, 20201, 21011, 21101, 30011, 100103, 101021, 101111, 102101, 103001, 120011, 121001, 200003, 200201, 201011, 201101, 202001
Offset: 1

Views

Author

Amarnath Murthy, Jun 21 2001

Keywords

Examples

			1301 belongs to the sequence since it is a prime with sum of digits = 5.
		

Crossrefs

Cf. A000040 (primes), A007953 (sum of digits), A052219 (digit sum = 5).
Cf. A062339 (same for digit sum s = 4), A062337 (s = 7), and others listed in A244918 (s = 68).
Subsequence of A062340 (primes with sum of digits divisible by 5).

Programs

  • Magma
    [p: p in PrimesUpTo(250000) | &+Intseq(p) eq 5]; // Vincenzo Librandi, Jul 08 2014
    
  • Maple
    T:= n-> `if`(n=1, 5, sort(select(isprime, [seq(seq(seq(
        10^(n-1)+1+10^i+10^j+10^k, k=1..j), j=1..i), i=1..n-1),
        seq(10^(n-1)+3+10^i, i=1..n-1)]))[]):
    seq(T(n), n=1..8);  # Alois P. Heinz, Dec 28 2015
  • Mathematica
    Select[Prime[Range[20000]],Total[IntegerDigits[#]]==5&] (* Harvey P. Dale, Nov 24 2013 *)
  • PARI
    \\ From M. F. Hasler, Mar 09 2022: (Start)
    select( {is_A062341(p,s=5)=sumdigits(p)==s&&isprime(p)}, primes([1,10^6])) \\ 2nd optional parameter for similar sequences with other digit sums.
    A062341_upto_length(L,s=5,a=List(),u=[10^k|k<-[0..L-1]])={forvec(d=[[1,L]|i<-[1..s]], isprime(p=vecsum(vecextract(u,d))) && listput(a,p),1); Set(a)} \\ (End)
  • Python
    from sympy import primerange as primes
    def ok(p): return sum(map(int, str(p))) == 5
    print(list(filter(ok, primes(1, 202002)))) # Michael S. Branicky, May 23 2021
    

Formula

Intersection of A000040 (primes) with A052219 (digit sum 5). - M. F. Hasler, Mar 09 2022

Extensions

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jul 06 2001

A062343 Primes whose sum of digits is 8.

Original entry on oeis.org

17, 53, 71, 107, 233, 251, 431, 503, 521, 701, 1061, 1151, 1223, 1511, 1601, 2141, 2213, 2411, 3023, 3041, 3203, 3221, 4013, 4211, 5003, 5021, 6011, 6101, 7001, 10007, 10061, 10133, 10151, 10223, 10313, 10331, 10601, 11213, 11321, 11411
Offset: 1

Views

Author

Amarnath Murthy, Jun 21 2001

Keywords

Examples

			1151 belongs to the sequence since it is a prime with sum of digits = 8.
		

Crossrefs

Cf. A000040 (primes), A007953 (sum of digits), A052222 (digit sum = 8).
Cf. A062339 (same for digit sum s = 4), A062341 (s = 5), A062337 (s = 7), A107579 (s = 10), and others listed in A244918 (s = 68).
Subsequence of A062342 (primes with digit sum divisible by 8).

Programs

  • Magma
    [p: p in PrimesUpTo(20000) | &+Intseq(p) eq 8]; // Vincenzo Librandi, Jul 08 2014
    
  • Maple
    A062343 := proc(n)
        option remember ;
        local p ;
        if n = 1 then
            17;
        else
            p := nextprime(procname(n-1)) ;
            while true do
                if digsum(p) = 8 then # digsum in oeis.org/transforms.txt
                    return p;
                else
                    p := nextprime(p) ;
                end if;
            end do:
        end if;
    end proc:
    seq(A062343(n),n=1..80) ; # R. J. Mathar, May 22 2025
  • Mathematica
    Select[Prime[Range[500000]], Total[IntegerDigits[#]]==8 &] (* Vincenzo Librandi, Jul 08 2014 *)
  • PARI
    select( {is_A062343(p, s=8)=sumdigits(p)==s&&isprime(p)}, primes([1, 12345])) \\ 2nd optional parameter for similar sequences with other digit sums. M. F. Hasler, Mar 09 2022
    
  • PARI
    {A062343_upto_length(L, s=8, a=List(), u=[10^(L-k)|k<-[1..L]])=forvec(d=[[1, L]|i<-[1..s]], isprime(p=vecsum(vecextract(u, d))) && listput(a, p), 1); Vecrev(a)} \\ M. F. Hasler, Mar 09 2022

Formula

Intersection of A000040 (primes) and A052222 (digit sum 8). - M. F. Hasler, Mar 09 2022

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Jul 06 2001

A107579 Primes with digit sum 10.

Original entry on oeis.org

19, 37, 73, 109, 127, 163, 181, 271, 307, 433, 523, 541, 613, 631, 811, 1009, 1063, 1117, 1153, 1171, 1423, 1531, 1621, 1801, 2017, 2053, 2143, 2161, 2251, 2341, 2503, 2521, 3061, 3313, 3331, 3511, 4051, 4231, 5023, 5113, 6121, 6211, 6301, 8011, 8101
Offset: 1

Views

Author

Zak Seidov, May 16 2005

Keywords

Comments

Subset of A061237 and A117674.

Crossrefs

Cf. A000040 (primes), A007953 (sum of digits), A052224 (digit sum = 10).
Cf. A061237 (sum of digits == 1 (mod 9)).
Subsequence of A062340 (primes with digit sum divisible by 5).
Cf. A062339 (same for digit sum s = 4), A062341 (s = 5), A062343 (s = 8), A106754 (s = 11), and others listed in A244918 (s = 68).

Programs

  • Magma
    [p: p in PrimesUpTo(10000) | &+Intseq(p) eq 10]; // Vincenzo Librandi, Jul 08 2014
    
  • Maple
    a:=proc(n) local nn: nn:=convert(n,base,10): if isprime(n)=true and add(nn[j], j=1..nops(nn))=10 then n else end if end proc: seq(a(n),n=1..10^4); # Emeric Deutsch, Mar 06 2008
  • Mathematica
    Select[Prime[Range[100000]], Total[IntegerDigits[#]]==10 &] (* Vincenzo Librandi, Jul 08 2014 *)
  • PARI
    forprime(p=19,8101,if(10==sumdigits(p),print(p","))) \\ Zak Seidov, Oct 08 2016
    
  • PARI
    (A107579_nxt(p)=until(isprime(p=A228915(p)),); p); A107579_first(N=100)=vector(N, i, p=if(i>1, A107579_nxt(p), 19)) \\ M. F. Hasler, Mar 15 2022
    
  • Python
    from itertools import count, islice
    from sympy import isprime
    from sympy.utilities.iterables import multiset_permutations
    def agen(b=10, sod=10): # generator for any base, sum-of-digits
        if 0 <= sod < b:
            yield sod
        nzdigs = [i for i in range(1, b) if i <= sod]
        nzmultiset = []
        for d in range(1, b):
            nzmultiset += [d]*(sod//d)
        for d in count(2):
            fullmultiset = [0]*(d-1-(sod-1)//(b-1)) + nzmultiset
            for firstdig in nzdigs:
                target_sum, restmultiset = sod - int(firstdig), fullmultiset[:]
                restmultiset.remove(firstdig)
                for p in multiset_permutations(restmultiset, d-1):
                    if sum(p) == target_sum:
                        t = int("".join(map(str, [firstdig]+p)), b)
                        if isprime(t):
                            yield t
                        if p[0] == target_sum:
                            break
    print(list(islice(agen(), 45))) # Michael S. Branicky, Mar 10 2022
    
  • Python
    from sympy import isprime
    def A107579(p=19):
        "Return a generator of the sequence of all primes >= p with the same digit sum as p."
        while True:
            if isprime(p): yield p
            p = A228915(p) # skip to next larger integer with the same digit sum
    a=A107579(); [next(a) for  in range(50)] # _M. F. Hasler, Mar 16 2022

Formula

Intersection of A000040 (primes) and A052224 (digit sum = 10). - M. F. Hasler, Mar 09 2022

Extensions

Edited by N. J. A. Sloane, Feb 20 2009 at the suggestion of Pacha Nambi

A106754 Primes p with digital sum equal to 11.

Original entry on oeis.org

29, 47, 83, 137, 173, 191, 227, 263, 281, 317, 353, 443, 461, 641, 821, 911, 1019, 1091, 1109, 1163, 1181, 1217, 1307, 1361, 1433, 1451, 1523, 1613, 1721, 1811, 1901, 2027, 2063, 2081, 2153, 2207, 2243, 2333, 2351, 2423, 2441, 2531, 2621, 2711, 2801, 3251
Offset: 1

Views

Author

Zak Seidov, May 16 2005

Keywords

Crossrefs

Cf. A000040 (primes), A007953 (sum of digits), A166311 (digit sum = 11).
Cf. A062339 (same for digit sum s = 4), ..., A107579 (s = 10), A106755 (s = 13), and others listed in A244918 (s = 68).
Subsequence of A119891 (prime trios: chain of prime sums of digits; also has as subsequence A106762 (s = 23), A106774 (s = 41), etc).

Programs

  • Magma
    [p: p in PrimesUpTo(10000) | &+Intseq(p) eq 11]; // Vincenzo Librandi, Jul 08 2014
    
  • Mathematica
    Select[Prime[Range[100000]], Total[IntegerDigits[#]]==11 &] (* Vincenzo Librandi, Jul 08 2014 *)
  • PARI
    select( {is_A106754(n)=sumdigits(n)==11&&isprime(n)}, primes([1, 3333])) \\ M. F. Hasler, Mar 09 2022

Formula

Intersection of A000040 (primes) and A166311 (digit sum = 11), also equals { p in A000040 | A007953(p) = 11 }. - M. F. Hasler, Mar 09 2022

A056807 Numbers k such that 3*10^k + 1 is prime.

Original entry on oeis.org

1, 3, 7, 10, 28, 36, 67, 81, 147, 483, 643, 1020, 1900, 2620, 10453, 27720, 52824, 105589, 111988, 618853, 665829
Offset: 1

Views

Author

Robert G. Wilson v, Aug 22 2000

Keywords

Examples

			k = 3 gives (3*10^3+1) = 3000+1 = 3001, which is prime.
		

Crossrefs

Programs

  • Mathematica
    Do[ If[ PrimeQ[ 3*10^k + 1], Print[ k ]], {k, 0, 20000}]
  • PARI
    is(k)=isprime(3*10^k+1) \\ Charles R Greathouse IV, Feb 17 2017

Formula

a(n) = A101823(n) + 1.

Extensions

a(13)-a(14) from Julien Peter Benney (jpbenney(AT)ftml.net), Nov 23 2004
a(15) from Hugo Pfoertner, Jan 18 2005
a(16)-a(17) from Robert G. Wilson v, Jan 18 2005
a(18) from Roman Makarchuk, Dec 05 2008 confirmed as next term by Ray Chandler, Mar 02 2012
a(19) from Alexander Gramolin, Feb 24 2012 confirmed as next term by Ray Chandler, Mar 02 2012
a(20)-a(21) from Kamada data by Robert Price, Jan 26 2015

A107618 Primes with digit sum = 64.

Original entry on oeis.org

19999999, 29999899, 29999989, 39979999, 39999979, 47999899, 48899899, 48989989, 48997999, 48999799, 48999889, 49989799, 49999699, 49999897, 56999989, 58799899, 58898989, 58988899, 58997899, 59698999, 59788999
Offset: 1

Views

Author

Zak Seidov, May 18 2005

Keywords

Crossrefs

Cf. similar sequences listed in A244918.

Programs

  • Magma
    [p: p in PrimesUpTo(69000000) | &+Intseq(p) eq 64]; // Vincenzo Librandi, Jul 09 2014
  • Mathematica
    Select[Prime[Range[3600000]],Total[IntegerDigits[#]]==64&] (* Harvey P. Dale, Jan 19 2012 *)

A107617 Primes with digit sum = 62.

Original entry on oeis.org

9899999, 18899999, 18999989, 19899989, 19998899, 19998989, 27989999, 27999899, 28998989, 28999979, 29789999, 29798999, 29969999, 29979899, 29988899, 29988989, 29989889, 29997899, 29998799, 29998889, 29999699, 36998999
Offset: 1

Views

Author

Zak Seidov, May 18 2005

Keywords

Crossrefs

Cf. similar sequences listed in A244918.

Programs

  • Magma
    [p: p in PrimesUpTo(38000000) | &+Intseq(p) eq 62]; // Vincenzo Librandi, Jul 09 2014
  • Mathematica
    Select[Prime[Range[600000]], Total[IntegerDigits[#]]==62 &] (* Vincenzo Librandi, Jul 09 2014 *)

A157711 Primes made up of 0's and four 1's only.

Original entry on oeis.org

10111, 1011001, 1100101, 10010101, 10100011, 101001001, 1000001011, 1000010101, 1010000011, 1100010001, 10000001101, 10001000011, 10001001001, 10001100001, 10100000011, 10100001001, 11000000101, 11001000001
Offset: 1

Views

Author

Lekraj Beedassy, Mar 04 2009

Keywords

Comments

Intersection of A062339 and A020449. Subsequence of A235154. - Felix Fröhlich, Nov 19 2014
Primes that are the sum of four distinct powers of ten (A038446). - Jeppe Stig Nielsen, May 18 2023

Crossrefs

Cf. A020449, A038446, A062339, A235154, A383675 (number of n-digit terms).

Programs

  • Maple
    for d from 4 to 18 do for c from 0 to 2^d-1 do bdgs := convert(c,base,2) ; if add(i,i=bdgs) = 3 then p := 10^d+add(op(i,bdgs)*10^(i-1),i=1..nops(bdgs)) ; if isprime(p) then printf("%d,",p) ; fi; fi; od: od: # R. J. Mathar, Mar 06 2009
  • Mathematica
    Flatten[Select[FromDigits/@Permutations[Join[{1,1,1,1},PadRight[{},7,0]]],PrimeQ]] // Union (* Harvey P. Dale, May 09 2019 *)
  • PARI
    for(n=0, 10, forprime(p=10^n, (10^(n+1)-1)/9, if(vecmax(digits(p))==1, if(sumdigits(p)==4, print1(p, ", "))))) \\ Felix Fröhlich, Nov 19 2014
    
  • PARI
    my(M=20);for(i=3, M, for(j=2,i-1, for(k=1, j-1, my(p=10^i+10^j+10^k+1); isprime(p)&&print1(p,", ")))) \\ Jeppe Stig Nielsen, May 18 2023

Extensions

Extended by numerous authors, Mar 06 2009
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