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 1-9 of 9 results.

A199340 Primes having only {0, 3, 4} as digits.

Original entry on oeis.org

3, 43, 433, 443, 3343, 3433, 4003, 30403, 33343, 33403, 34033, 34303, 34403, 40343, 40433, 43003, 43403, 300043, 300343, 304033, 304303, 304433, 330433, 333433, 334043, 334333, 334403, 343303, 343333, 343433, 400033, 403003, 403043, 403433, 430303, 430333
Offset: 1

Views

Author

M. F. Hasler, Nov 05 2011

Keywords

Comments

All terms end in '3'. This could be used to speed up the given program.
A020461 is a subsequence. - Vincenzo Librandi, Jul 23 2015

Crossrefs

Cf. Primes that contain only the digits (3,4,k): this sequence (k=0), A199341 (k=1), A199342 (k=2), A199345 (k=5), A199346 (k=6), A199347 (k=7), A199348 (k=8), A199349 (k=9).

Programs

  • Magma
    [p: p in PrimesUpTo(5*10^5) | Set(Intseq(p)) subset [3, 4, 0]]; // Vincenzo Librandi, Jul 23 2015
    
  • Mathematica
    Select[Prime[Range[5 10^4]], Complement[IntegerDigits[#], {3, 4, 0}]=={} &] (* Vincenzo Librandi, Jul 23 2015 *)
    Select[FromDigits/@Tuples[{0,3,4},6],PrimeQ] (* Harvey P. Dale, Mar 21 2020 *)
    Select[10#+3&/@FromDigits/@Tuples[{0,3,4},5],PrimeQ] (* Harvey P. Dale, May 02 2022 *)
  • PARI
    a(n, list=0, L=[0, 3, 4], reqpal=0)={my(t); for(d=1, 1e9, u=vector(d, i, 10^(d-i))~; forvec(v=vector(d, i, [1+(i==1&!L[1]), #L]), isprime(t=vector(d, i, L[v[i]])*u)||next; reqpal && !isprime(A004086(t)) && next; list && print1(t", "); n--||return(t)))} \\ Syntax updated for current PARI version. - M. F. Hasler, Jul 25 2015
    
  • PARI
    {forprime(p=3,1e6,p%10==3&&!setminus(Set(digits(p)),[3,4])&&print1(p","))} \\ [0] evaluates to false. - M. F. Hasler, Jul 25 2015

A058429 Numbers k such that k^2 contains only digits {0,3,4}, not ending with zero.

Original entry on oeis.org

2, 548, 585688, 58591812, 200824138, 5773251280200207952, 20832739723817975138362
Offset: 1

Views

Author

Patrick De Geest, Nov 15 2000

Keywords

Crossrefs

Cf. A058430.

Programs

  • PARI
    \\ From M. F. Hasler, May 14 2007, edited Nov 14 2017: (Start)
    admissibleMod(LIM=10000)={ local( t=[4], tt=1 ); while( LIM > tt*=10, t=concat([t,t+vector(#t,i,3)*tt,t+vector(#t,i,4)*tt])); /*print("t="t);*/ t=Set(t); tt=[]; for(i=1,LIM, setsearch(t,i^2%LIM) && tt=concat(tt,i)); concat(tt,LIM+tt[1])}
    A058429(Nmax=1e19,N=2,addMod=100000,debug=1)={my( a=[], Nnext, N2, numDigits, place, addNext=admissibleMod(addMod=round(addMod)), d=1, add=vector(addMod,i,if(i-1>addNext[d],d++);addNext[d]-i+1), nextOK=[0,2,1,0,0,5,4,3,2,1], pow10 = vector( d=#Str((Nmax=round(Nmax))^2), i, 10^(i-1)) ); nextOK = vector( #nextOK, i, if( nextOK[i],nextOK[i]*pow10)); N=round(N); while( Nmax >= N, numDigits = #Str(N2=N^2); 3 > N2 \ pow10[numDigits] && N = sqrtint( 3*pow10[numDigits]+3 )+1; Nnext = min( Nmax, sqrtint(pow10[numDigits]*10)\3*2); if( debug, print( "checking from "N" to "Nnext": <= ",1+max(0,Nnext-N)*(#addNext-1) \ addMod," candidates.")); N += add[1+ N%addMod]; place=1; while( Nnext >= N, dr = divrem( N2=N^2, pow10[ place=numDigits ] ); while( place-- && !d=nextOK[1+ (dr = divrem( dr[2], pow10[ place ] ))[1]], ); place || break; N = sqrtint( N2 - dr[2] + d[ place ])+1; N+=add[1+N%addMod]); if( !place, debug && print( N, "^2 = ", N^2); a=concat(a,N); N=Nnext+1 ); N=Nnext*5\2);a } \\ (End)

Extensions

a(6) from M. F. Hasler, May 14 2007
a(7) from Mishima's page added by Max Alekseyev, Jul 13 2009

A119059 Triangular numbers composed of digits {0,3,4}.

Original entry on oeis.org

3, 300, 3003, 3403, 3444000, 344334403, 433430403, 3434340003, 4033034303403, 3430000044444403, 4333004330434300, 300034434334030003, 333343033034040030, 44400033434030304430, 3340004334430334340000, 30340003004344033440000, 4430044300033330340443003
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Crossrefs

Cf. A000217, A058430, A119060. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119060(n)). - Michel Marcus, Mar 22 2023

Extensions

a(16)-a(17) from Tyler Busby, Mar 22 2023

A294660 Least nonnegative integer not occurring earlier whose square has no digit in common with the square of the previous term, a(0) = 0.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 9, 8, 10, 15, 12, 16, 20, 11, 22, 13, 18, 14, 28, 19, 17, 21, 23, 26, 29, 24, 30, 25, 33, 58, 27, 34, 47, 38, 45, 31, 48, 41, 50, 37, 52, 44, 65, 40, 57, 76, 32, 63, 35, 60, 39, 62, 36, 88, 46, 67, 51, 183, 75, 43, 55, 42, 53, 56, 70, 61, 64, 85, 59, 77, 69, 73, 78, 89
Offset: 0

Views

Author

M. F. Hasler, Nov 08 2017

Keywords

Comments

This is not a permutation of the nonnegative integers, since numbers whose square has all digits '1' through '9' (cf. A294661, e.g., 11826 with 11826^2 = 139854276) can never appear - and these numbers have asymptotic density 1.
Will all integers whose square does not have all of the digits 1-9, eventually appear? Or might the sequence be finite? Since a(n)^2 has no digits in common with a(n-1)^2, it is sufficient for a(n+1) to exist, to find a number whose square has a subset of the digits of a(n-1)^2. Is this always possible? This problem sometimes has only "sporadic k-digital solutions", see, e.g., A058430, A030175, ... and the link to De Geest's page.

Examples

			Since a(7)^2 = 7^2 = 49, the subsequent term cannot be 8, since 8^2 = 64 has the digit 4 in common with 49. Therefore, a(8) = 9, with 9^2 = 81 having no common digit with 49.
a(1201) = 1037. So the square of the next term must not have any of the digits in {0, 1, 3, 5, 6, 7, 9}, only 2, 4, 8 are allowed. The least such number that has not been used before is a(1202) = 210912978, with a(1202)^2 = 210912978^2 = 44484284288828484. - _Alois P. Heinz_, Nov 09 2017
		

Crossrefs

Cf. A030287 (strictly increasing), A067581 (do not take squares).

Programs

  • PARI
    {u=a=0; for(n=0, 99, print1(a", "); u+=1<
    				
  • PARI
    {u=[a=0]; for(n=0, 99, print1(a", "); D=Set(if(a, digits(a^2))); for(k=u[1]+1, oo, setsearch(u, k)&&next; #setintersect(D, Set(digits(k^2)))&&next; u=setunion(u,[a=k]); break); while(#u>1&&u[2]==u[1]+1,u=u[^1])); a}

A136927 Numbers k such that k and k^2 use only the digits 0, 3, 4, 5 and 6.

Original entry on oeis.org

0, 6, 60, 66, 600, 656, 660, 666, 6000, 6560, 6600, 6660, 6666, 60000, 63566, 65600, 66000, 66600, 66660, 66666, 600000, 603656, 604434, 635660, 656000, 660000, 660656, 666000, 666600, 666660, 666666, 6000000, 6036560, 6044340, 6356600, 6560000, 6600000, 6606560, 6660000, 6666000, 6666600, 6666660, 6666666, 60000000, 60054434, 60365600
Offset: 1

Views

Author

Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008

Keywords

Comments

Generated with DrScheme.
See also A058429-A058430. - M. F. Hasler, Jan 24 2008

Examples

			665605465350506^2 = 443030635504463643353434456036.
		

Programs

  • Mathematica
    With[{c={0,3,4,5,6},nn=8},Select[FromDigits/@Tuples[c,nn],SubsetQ[ c,IntegerDigits[ #^2]]&]] (* Harvey P. Dale, Apr 27 2022 *)

A136928 Numbers k such that k and k^2 use only the digits 0, 3, 4, 5 and 8.

Original entry on oeis.org

0, 548, 5480, 54800, 55548, 548000, 555388, 555480, 588048, 5480000, 5553880, 5554548, 5554800, 5834388, 5880480, 54800000, 55538800, 55545480, 55548000, 58343880, 58804800, 548000000, 550500548, 555388000, 555454800, 555480000, 583438800, 588048000, 5480000000, 5505005480, 5553880000, 5554548000, 5554800000, 5834388000
Offset: 1

Views

Author

Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008

Keywords

Comments

Generated with DrScheme.

Examples

			583854308054548^2 = 340885853033855033588543484304.
		

Crossrefs

See also A058429-A058430. - M. F. Hasler, Jan 24 2008

A136929 Numbers k such that k and k^2 use only the digits 0, 3, 4, 5 and 9.

Original entry on oeis.org

0, 3, 30, 300, 3000, 30000, 30503, 30903, 300000, 305030, 309030, 550503, 950503, 953903, 3000000, 3005003, 3009003, 3050300, 3055003, 3090300, 5505030, 9505030, 9539030, 30000000, 30050030, 30090030, 30503000, 30550030, 30903000, 55050300, 95050300, 95055003, 95390300, 300000000, 300050003, 300050503, 300090003, 300500300
Offset: 1

Views

Author

Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008

Keywords

Comments

Generated with DrScheme.
See also A058429-A058430. - M. F. Hasler, Jan 24 2008

Examples

			950439335440903^2 = 903334930353345333433405455409.
		

A136930 Numbers k such that k and k^2 use only the digits 0, 3, 4, 6 and 7.

Original entry on oeis.org

0, 6, 60, 600, 6000, 60000, 66076, 600000, 660760, 6000000, 6607600, 60000000, 60003706, 60036706, 66036076, 66066376, 66076000, 600000000, 600037060, 600306344, 600367060, 600373006, 606336074, 660360760, 660663760, 660760000, 660760474, 6000000000, 6000036706, 6000370600, 6000637006, 6003063440, 6003670600, 6003730060
Offset: 1

Views

Author

Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008

Keywords

Comments

Generated with DrScheme.
See also A058429-A058430. - M. F. Hasler, Jan 24 2008

Examples

			660760703770306^2 = 436604707647030077763607333636.
		

A136931 Numbers k such that k and k^2 use only the digits 0, 3, 4, 6 and 8.

Original entry on oeis.org

0, 6, 8, 60, 80, 600, 800, 6000, 6638, 6808, 6844, 8000, 60000, 60406, 60688, 66380, 66808, 68080, 68440, 80000, 600000, 604060, 606880, 663800, 668080, 680800, 684400, 800000, 6000000, 6003406, 6004006, 6040600, 6068800, 6638000, 6680800, 6808000, 6844000, 8000000, 60000000, 60034060, 60040060, 60406000, 60688000, 66363008, 66380000
Offset: 1

Views

Author

Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008

Keywords

Comments

Generated with DrScheme.

Examples

			683084686436344^2 = 466604688843838404646364086336.
		

Crossrefs

See also A058429-A058430. - M. F. Hasler, Jan 24 2008

Programs

  • Mathematica
    s={0,3,4,6,8}; Select[Range[0,10^6], SubsetQ[s, Sort[DeleteDuplicates[IntegerDigits[#]]]] && SubsetQ[s, Sort[DeleteDuplicates[IntegerDigits[#^2]]]] &] (* Stefano Spezia, Aug 11 2025 *)
Showing 1-9 of 9 results.