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 15 results. Next

A061511 a(0) = 0; a(n) is obtained by incrementing each digit of a(n-1) by 1.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 21, 32, 43, 54, 65, 76, 87, 98, 109, 2110, 3221, 4332, 5443, 6554, 7665, 8776, 9887, 10998, 2110109, 32212110, 43323221, 54434332, 65545443, 76656554, 87767665, 98878776, 109989887, 211010910998
Offset: 0

Views

Author

Amarnath Murthy, May 08 2001

Keywords

Comments

In A061511-A061522, A061746-A061750 when the incremented digit exceeds 9 it is written as a 2-digit string. So 9+1 becomes the 2-digit string 10, etc.
a(n+10) is the concatenation of a(n) and a(n-1).
Considering each term as a sequence of digits, each of the subsequences a(9n), a(9n-1), ... and a(9n-8) converges to a different limit. - M. F. Hasler, Jun 24 2016

Examples

			Following 43: 4+1 = 5 and 3+1 = 4, hence the next term is 54.
		

Crossrefs

Programs

  • Mathematica
    NestList[FromDigits[Flatten[IntegerDigits[IntegerDigits[#]+1]]]&,0,38] (* Jayanta Basu, May 18 2013 *)
  • PARI
    A061511(n=2, a=n>0, m=1)={for(n=2, n, a=eval(concat(apply(t->Str(t+m), digits(a))))); a} \\ If only the 2nd argument is given, then the operation is applied once to that argument. - M. F. Hasler, Jun 24 2016

A061581 a(1) = 1, a(n) = number obtained by replacing each digit of a(n-1) with its double.

Original entry on oeis.org

1, 2, 4, 8, 16, 212, 424, 848, 16816, 21216212, 424212424, 848424848, 1681684816816, 212162121681621216212, 42421242421216212424212424, 848424848424212424848424848, 16816848168168484248481681684816816
Offset: 1

Views

Author

Amarnath Murthy, May 13 2001

Keywords

Comments

It might have been more natural to start with index / offset 0. - M. F. Hasler, Jun 24 2016

Examples

			The term after 16 is 2.12, i.e., 212.
		

Crossrefs

Programs

  • Maple
    a:= proc(n) option remember; `if`(n=1, 1, (l->
           parse(cat(seq(2*l[-i], i=1..nops(l)))))(
                 convert(a(n-1), base, 10)))
        end:
    seq(a(n), n=1..20);  # Alois P. Heinz, Jun 24 2016
  • Mathematica
    NestList[FromDigits[Flatten[IntegerDigits[2*IntegerDigits[#]]]] &,1,16] (* Jayanta Basu, May 20 2013 *)
  • PARI
    A061581(n=2,a=1,m=2)={while(n--,a=eval(concat(apply(t->Str(t),digits(a)*m))));a} \\ If only the 2nd argument is given, then the operation is applied once to that argument. - M. F. Hasler, Jun 24 2016

Extensions

More terms from Larry Reeves (larryr(AT)acm.org) and Asher Auel, May 15 2001

A061750 a(0) = 0; a(n) is obtained by incrementing each digit of a(n-1) by 9.

Original entry on oeis.org

0, 9, 18, 1017, 1091016, 109181091015, 109181017109181091014, 1091810171091016109181017109181091013, 10918101710910161091810910151091810171091016109181017109181091012
Offset: 0

Views

Author

Amarnath Murthy, May 08 2001

Keywords

Comments

In A061511-A061522, A061746-A061750 when the incremented digit exceeds 9 it is written as a 2-digit string. So 9+1 becomes the 2-digit string 10, etc.
Considering each term as a sequence of digits, the sequence converges to the limit 109181017109101610918109..... - M. F. Hasler, Jun 24 2016
a(13) has 1078 decimal digits. - Michael De Vlieger, Jun 24 2016

Crossrefs

Programs

  • Mathematica
    NestList[FromDigits@ Flatten@ Map[IntegerDigits, IntegerDigits@ # + 9] &, 0, 8] (* Michael De Vlieger, Jun 24 2016, after Harvey P. Dale at A061512 *)
  • PARI
    A061750(n=2, a=9, m=9)={for(n=2,n, a=eval(concat(apply(t->Str(t+m), digits(a)))));if(n,a)} \\ If only the 2nd argument is given, then the operation is applied once to that argument. - M. F. Hasler, Jun 24 2016

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), May 11 2001

A061746 a(0) = 1; a(n) is obtained by incrementing each digit of a(n-1) by 7.

Original entry on oeis.org

1, 8, 15, 812, 1589, 8121516, 1589812813, 8121516158915810, 158981281381215168121587, 8121516158915810158981281315898121514, 158981281381215168121587812151615891581081215161589812811
Offset: 0

Views

Author

Amarnath Murthy, May 08 2001

Keywords

Comments

In A061511-A061522, A061746-A061750 when the incremented digit exceeds 9 it is written as a 2-digit string. So 9+1 becomes the 2-digit string 10, etc.
Considering each term as a sequence of digits, the subsequences a(2n) and a(2n-1) converge to two different fixed points of the operation repeated twice, 158981281381... and 81215161589158.... - M. F. Hasler, Jun 24 2016

Crossrefs

Programs

  • Mathematica
    NestList[FromDigits[Flatten[IntegerDigits/@(IntegerDigits[#]+7)]]&,1,10] (* Harvey P. Dale, Jun 07 2025 *)
  • PARI
    A061746(n=1, a=1, m=7)={for(n=1, n, a=eval(concat(apply(t->Str(t+m), digits(a))))); a} \\ If only the 2nd argument is given, then the operation is applied once to that argument. - M. F. Hasler, Jun 24 2016

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), May 11 2001

A061582 a(1) = 1, a(n) = number obtained by replacing each digit of a(n-1) with three times its value.

Original entry on oeis.org

1, 3, 9, 27, 621, 1863, 324189, 961232427, 2718369612621, 6213249182718361863, 1863961227324621324918324189, 32418927183662196121863961227324961232427, 961232427621324918186327183632418927183662196122718369612621
Offset: 1

Views

Author

Amarnath Murthy, May 13 2001

Keywords

Comments

Number of digits of each term in this sequence is sequence A000930. - Dmitry Kamenetsky, Jan 17 2009
Each of the subsequences a(5n), a(5n-1), ..., a(5n-4) seem to converge to a different fixed point of the operation (if the terms are seen as sequences of digits). - M. F. Hasler, Jun 24 2016
a(20) has 1278 decimal digits. - Michael De Vlieger, Jun 24 2016

Crossrefs

Programs

  • Mathematica
    NestList[FromDigits@ Flatten@ Map[IntegerDigits, 3 IntegerDigits@ #] &, 1, 12] (* Michael De Vlieger, Jun 24 2016 *)
  • PARI
    A061582(n=2,a=1,m=3)={while(n--,a=eval(concat(apply(t->Str(t),digits(a)*m))));a} \\ If only the 2nd argument is given, then the operation is applied once to that argument. - M. F. Hasler, Jun 24 2016

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), May 14 2001

A061586 a(1) = 1, a(n)= number obtained by replacing each digit of a(n-1) with eight times its value.

Original entry on oeis.org

1, 8, 64, 4832, 32642416, 241648321632848, 1632848326424168482416643264, 84824166432642416483216328486432641632848483224164832, 64326416328484832241648321632848326424168482416643264483224164832848241664326432642416163284832642416
Offset: 1

Views

Author

Amarnath Murthy, May 13 2001

Keywords

Crossrefs

Programs

  • Mathematica
    NestList[FromDigits[Flatten[IntegerDigits/@(8*IntegerDigits[#])]]&,1,10] (* Harvey P. Dale, Sep 22 2012 *)
  • Python
    def A061586_first(n):
        an = "1"
        cnt = 1
        a061586 = []
        while cnt < n:
            a061586.append(int(an))
            newan = ""
            for i in an:
                newan += str(8*int(i))
            an = newan
            cnt += 1
        a061586.append(int(an))
        return a061586 # John Cerkan, May 25 2018

Extensions

More terms from Larry Reeves (larryr(AT)acm.org) and Asher Auel, May 15 2001

A061512 a(0) = 1; a(n) is obtained by incrementing each digit of a(n-1) by 2.

Original entry on oeis.org

1, 3, 5, 7, 9, 11, 33, 55, 77, 99, 1111, 3333, 5555, 7777, 9999, 11111111, 33333333, 55555555, 77777777, 99999999, 1111111111111111, 3333333333333333, 5555555555555555, 7777777777777777, 9999999999999999, 11111111111111111111111111111111, 33333333333333333333333333333333
Offset: 0

Views

Author

Amarnath Murthy, May 08 2001

Keywords

Comments

In A061511-A061522, A061746-A061750 when the incremented digit exceeds 9 it is written as a 2-digit string. So 9+1 becomes the 2-digit string 10, etc.
Also: odd repdigits (A010785) of length 2^k, cf. formula. - M. F. Hasler, Jun 24 2016

Examples

			Following 33: 3+2 = 5 and 3+2 = 5, hence the next term is 55.
		

Crossrefs

Programs

  • Mathematica
    NestList[FromDigits[Flatten[IntegerDigits/@(IntegerDigits[#]+2)]]&,1,30] (* Harvey P. Dale, Apr 13 2012 *)
  • PARI
    A061512(n)=10^2^(n\5)\9*(n%5*2+1) \\ M. F. Hasler, Jun 24 2016
    
  • PARI
    nxt(n) = my(d=digits(n)); if(d[1]<9,n+2*(10^#d - 1)/9,(10^(2*#d) - 1)/9)
    inv(n) = {my(d=digits(n));5*logint(#d,2) + (d[1]+1)\2} \\ David A. Corneth, Jun 24 2016

Formula

a(n) = (10^2^floor(n/5)-1)/9*(n%5*2+1), where n%5 means the remainder (in {0..4}) of n divided by 5. - M. F. Hasler, Jun 24 2016

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), May 11 2001

A061583 a(1) = 1, a(n) is the number obtained by replacing each digit of a(n-1) with five times its value.

Original entry on oeis.org

1, 5, 25, 1025, 501025, 250501025, 10250250501025, 501025010250250501025, 2505010250501025010250250501025, 1025025050102502505010250501025010250250501025
Offset: 1

Views

Author

Amarnath Murthy, May 13 2001

Keywords

Comments

Number of digits of each term is the sequence A038718. - Dmitry Kamenetsky, Jan 17 2009

Crossrefs

Programs

  • Maple
    a:= proc(n) option remember; `if`(n=1, 1, (s-> parse(cat(
          seq(parse(s[i])*5, i=1..length(s)))))(""||(a(n-1))))
        end:
    seq(a(n), n=1..10);  # Alois P. Heinz, May 25 2018
  • Mathematica
    NestList[FromDigits[Flatten[IntegerDigits/@(5*IntegerDigits[#])]]&,1,10] (* Harvey P. Dale, Dec 31 2013 *)
  • Python
    def A061583_first(n):
        an = "1"
        a061583 = []
        while n > 1:
            a061583.append(int(an))
            newan = ""
            for i in an:
                newan += str(5*int(i))
            an = newan
            n -= 1
        a061583.append(int(an))
        return a061583 # John Cerkan, May 25 2018

Extensions

More terms from Larry Reeves (larryr(AT)acm.org) and Asher Auel, May 15 2001

A061584 a(1) = 1, a(n)= number obtained by replacing each digit of a(n-1) with six times its value.

Original entry on oeis.org

1, 6, 36, 1836, 6481836, 3624486481836, 1836122424483624486481836, 64818366121224122424481836122424483624486481836, 362448648183636612612122461212241224244864818366121224122424481836122424483624486481836
Offset: 1

Views

Author

Amarnath Murthy, May 13 2001

Keywords

Comments

a(n) contains all of a(n-1) as its least significant digits.

Crossrefs

Programs

  • Mathematica
    NestList[FromDigits[Flatten[IntegerDigits/@(6 IntegerDigits[#])]]&,1,10] (* Harvey P. Dale, Aug 26 2022 *)
  • Python
    def A061584_first(n):
        an = "1"
        a061584 = []
        while n > 1:
            a061584.append(int(an))
            newan = ""
            for i in an:
                newan += str(6*int(i))
            an = newan
            n -= 1
        a061584.append(int(an))
        return a061584 # John Cerkan, May 25 2018

Extensions

More terms from Larry Reeves (larryr(AT)acm.org) and Asher Auel, May 15 2001

A061585 a(1) = 1, a(n)= number obtained by replacing each digit of a(n-1) with seven times its value.

Original entry on oeis.org

1, 7, 49, 2863, 14564221, 72835422814147, 49145621352814145672872849, 286372835421472135145672872835424914564914562863, 1456422149145621352814728491472135728354249145649145621352814286372835422863728354214564221
Offset: 1

Views

Author

Amarnath Murthy, May 13 2001

Keywords

Crossrefs

Programs

  • Mathematica
    NestList[FromDigits[Flatten[IntegerDigits/@(7*IntegerDigits[#])]]&,1,10] (* Harvey P. Dale, Jan 23 2015 *)
  • PARI
    A061585(n=2,a=1,m=7)={while(n--,a=eval(concat(apply(t->Str(t),digits(a)*m))));a} \\ If only the 2nd argument is given, then the operation is applied once to that argument. - M. F. Hasler, Jun 24 2016
    
  • Python
    def A061585_first(n):
        an = "1"
        a061585 = []
        while n > 1:
            a061585.append(int(an))
            newan = ""
            for i in an:
                newan += str(7*int(i))
            an = newan
            n -= 1
        a061585.append(int(an))
        return a061585 # John Cerkan, May 25 2018

Extensions

More terms from Larry Reeves (larryr(AT)acm.org) and Asher Auel, May 15 2001
Corrected by Harvey P. Dale, Jan 23 2015
Showing 1-10 of 15 results. Next