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 37 results. Next

A095006 Number of evil primes (A027699) in range ]2^n,2^(n+1)].

Original entry on oeis.org

1, 1, 0, 3, 2, 5, 4, 23, 27, 62, 95, 222, 367, 777, 1269, 2910, 4859, 10140, 17714, 36714, 66020, 133400, 245959, 493532, 916913, 1822087, 3428633, 6782008, 12870735, 25339113, 48419194, 95194890, 182818705, 358637144, 691891351, 1355985684, 2625053871, 5142673207
Offset: 1

Views

Author

Antti Karttunen and Labos Elemer, Jun 01 2004

Keywords

Examples

			From _Michael De Vlieger_, Feb 27 2017: (Start)
a(2) = 1 since between 2^2 and 2^3 only the prime 5 (binary 11) has an even number of 1s.
a(3) = 0 since none of the primes between 2^3 and 2^4 have an even number of 1s in their binary expansions.
a(4) = 3 since the primes 17, 23, and 29 have an even number of 1s in their binary expansions (i.e., 10001, 10111, 11101). (End)
		

Crossrefs

Programs

  • Mathematica
    Table[m = Count[Prime@ Range[PrimePi[2^n] + 1, PrimePi[2^(n + 1) - 1]], k_ /; EvenQ@ DigitCount[k, 2, 1]]; Print@ m; m, {n, 24}] (* Michael De Vlieger, Feb 27 2017 *)

Formula

a(n) = A036378(n) - A095005(n).

Extensions

a(34)-a(38) from Amiram Eldar, Jun 20 2024

A177748 First primes of record chains of consecutive primes such that all of them are evil (A027699).

Original entry on oeis.org

3, 257, 337, 4423, 4919, 30431, 66841, 514271, 14490383, 231234569, 325923613, 640085473, 1600993259, 7180164577, 8069913503, 86933359951, 284331217637, 1128352801153, 1209935587291, 2454267258251, 2945783287813
Offset: 1

Views

Author

Vladimir Shevelev, Dec 12 2010

Keywords

Comments

The first lengths of such chains of primes are: 2, 3, 5, 7, 8, 12, 16, ..., cf. A177801.

Examples

			257 is the first evil prime followed by two consecutive primes (263,269) which are also evil. Thus it is record length 3.
		

Crossrefs

Cf. A001969, A000069, A027697, A027699, A177798 (odious version), A177801.

Programs

  • PARI
    {l=0;sp=0;r=0; forprime( p=1, default(primelimit), if( norml2(binary(p))%2, l>r & !print1(sp", ") & r=l; l & l=0, l || sp=p; l++))} \\ M. F. Hasler, Dec 12 2010

Extensions

More terms from D. S. McNeil, Dec 12 2010
a(18)-a(21) from Amiram Eldar, Dec 09 2020

A230353 Products of 3 evil primes (A027699) p,q,r, such that numbers p*q, p*r, q*r, and p*q*r are odious (A000069).

Original entry on oeis.org

575, 1775, 2075, 2225, 2825, 3475, 6575, 8381, 8675, 8825, 8975, 8993, 10235, 11225, 11675, 11975, 12035, 12167, 12905, 13075, 14275, 14825, 18745, 19925, 21575, 22881, 23943, 24389, 25325, 25775, 26765, 27575, 30189, 30925, 30981, 31433, 32223, 32675, 32975
Offset: 1

Views

Author

Keywords

Comments

These numbers are products of 3 evil numbers (A001969) but not represented as products of two evil numbers (A230213).

Examples

			For triple of evil primes {3,29,263} numbers 3*29 = 87, 3*263 = 789, 29*263 = 7627 and 3*29*263 = 22881. Thus 22881 is in the sequence.
		

Crossrefs

Programs

  • PARI
    od(n)=hammingweight(n)%2
    list(lim)=my(v=List(),pq); forprime(p=23,lim\25, if(od(p), next); forprime(q=5,min(lim\(3*p),p), if(od(q) || !od(pq=p*q), next); forprime(r=3,min(lim\pq,q), if(!od(r) && od(q*r) && od(p*r) && od(pq*r), listput(v, pq*r))))); vecsort(Vec(v)) \\ Charles R Greathouse IV, Nov 01 2013

A231254 Odious primes p (A027697) such that p^2 and p^3 are evil (A027699).

Original entry on oeis.org

37, 47, 107, 137, 233, 331, 463, 491, 557, 587, 607, 631, 653, 733, 823, 829, 883, 947, 971, 997, 1153, 1187, 1193, 1231, 1249, 1321, 1327, 1493, 1543, 1567, 1663, 1667, 1669, 1709, 1787, 1801, 1933, 1987, 2011, 2027, 2087, 2143, 2161, 2213, 2269, 2273, 2311
Offset: 1

Views

Author

Keywords

Comments

Sequence {a(n)^4} is a subsequence of A227891 such that a(1)^4 = 1874161 is the smallest power of an odious prime that is in A227891.

Crossrefs

Programs

  • Mathematica
    evilQ[n_]:=EvenQ[DigitCount[n,2][[1]]];
    odiousQ[n_]:=OddQ[DigitCount[n, 2][[1]]];
    Select[Range[2000],PrimeQ[#]&&odiousQ[#]&&evilQ[#^2]&&evilQ[#^3]&] (* Peter J. C. Moses, Nov 08 2013 *)

A360648 Fully multiplicative with a(A027697(k)) = A027699(k) and a(A027699(k)) = A027697(k) for any k > 0.

Original entry on oeis.org

1, 3, 2, 9, 7, 6, 5, 27, 4, 21, 17, 18, 23, 15, 14, 81, 11, 12, 29, 63, 10, 51, 13, 54, 49, 69, 8, 45, 19, 42, 43, 243, 34, 33, 35, 36, 53, 87, 46, 189, 71, 30, 31, 153, 28, 39, 83, 162, 25, 147, 22, 207, 37, 24, 119, 135, 58, 57, 89, 126, 101, 129, 20, 729
Offset: 1

Views

Author

Rémy Sigrist, Feb 15 2023

Keywords

Comments

In other words, we replace odious prime numbers with evil prime numbers and vice versa.
This sequence is a self-inverse permutation of the positive integers.

Examples

			For n = 84:
- 82 = 2^2 * 3 * 7,
- a(2) = a(A027697(1)) = A027699(1) = 3,
- a(3) = a(A027699(1)) = A027697(1) = 2,
- a(7) = a(A027697(2)) = A027699(2) = 5,
- so a(84) = 3^2 * 2 * 5 = 90.
		

Crossrefs

Programs

  • PARI
    See Links section.

A131122 Even numbers that are not the sum of an evil prime (A027699) and an odious prime (A027697).

Original entry on oeis.org

2, 4, 6, 8, 20, 26, 32, 38, 68, 86, 92, 98, 128, 164, 188, 278, 302, 512, 2048, 8192, 32768, 131072, 524288, 2097152, 8388608, 33554432, 134217728, 536870912
Offset: 1

Views

Author

T. D. Noe, Jun 15 2007

Keywords

Comments

Every power of 2 with an odd exponent is a term.
Every pair of primes that sum to 4^k, with k > 1, consists of an evil prime and an odious prime. The smallest example is 16 = 3+13 = 5+11; 3 and 5 are evil, 11 and 13 are odious.

Examples

			32 is here because 32 = 3+29 = 13+19, 3 and 29 are both odious, and 13 and 19 are both evil.
		

Crossrefs

Cf. A004171 (odd powers of 2), A027697, A027699.

Programs

  • PARI
    isok(n) = {if ((n % 2) == 0, forprime(p=3, n, if ((norml2(binary(p))%2==1) && (isprime(q=n-p)) && (!bittest(norml2(binary(q)), 0)), return (0));); return (1);); return(0);}
    lista(nn) = forstep(n=2, nn, 2, if (isok(n), print1(n, ", "))); \\ Michel Marcus, Oct 14 2018

Extensions

a(23)-a(28) from Michel Marcus, Oct 14 2018

A001969 Evil numbers: nonnegative integers with an even number of 1's in their binary expansion.

Original entry on oeis.org

0, 3, 5, 6, 9, 10, 12, 15, 17, 18, 20, 23, 24, 27, 29, 30, 33, 34, 36, 39, 40, 43, 45, 46, 48, 51, 53, 54, 57, 58, 60, 63, 65, 66, 68, 71, 72, 75, 77, 78, 80, 83, 85, 86, 89, 90, 92, 95, 96, 99, 101, 102, 105, 106, 108, 111, 113, 114, 116, 119, 120, 123, 125, 126, 129
Offset: 1

Views

Author

Keywords

Comments

This sequence and A000069 give the unique solution to the problem of splitting the nonnegative integers into two classes in such a way that sums of pairs of distinct elements from either class occur with the same multiplicities [Lambek and Moser]. Cf. A000028, A000379.
In French: les nombres païens.
Theorem: First differences give A036585. (Observed by Franklin T. Adams-Watters.)
Proof from Max Alekseyev, Aug 30 2006 (edited by N. J. A. Sloane, Jan 05 2021): (Start)
Observe that if the last bit of a(n) is deleted, we get the nonnegative numbers 0, 1, 2, 3, ... in order.
The last bit in a(n+1) is 1 iff the number of bits in n is odd, that is, iff A010060(n+1) is 1.
So, taking into account the different offsets here and in A010060, we have a(n) = 2*(n-1) + A010060(n-1).
Therefore the first differences of the present sequence equal 2 + first differences of A010060, which equals A036585. QED (End)
Integers k such that A010060(k-1)=0. - Benoit Cloitre, Nov 15 2003
Indices of zeros in the Thue-Morse sequence A010060 shifted by 1. - Tanya Khovanova, Feb 13 2009
Conjecture, checked up to 10^6: a(n) is also the sequence of numbers k representable as k = ror(x) XOR rol(x) (for some integer x) where ror(x)=A038572(x) is x rotated one binary place to the right, rol(x)=A006257(x) is x rotated one binary place to the left, and XOR is the binary exclusive-or operator. - Alex Ratushnyak, May 14 2016
From Charlie Neder, Oct 07 2018: (Start)
Conjecture is true: ror(x) and rol(x) have an even number of 1 bits in total (= 2 * A000120(x)), and XOR preserves the parity of this total, so the resulting number must have an even number of 1 bits. An x can be constructed corresponding to a(n) like so:
If the number of bits in a(n) is even, add a leading 0 so a(n) is 2k+1 bits long.
Do an inverse shuffle on a(n), then "divide" by 11, rotate the result k bits to the right, and shuffle to get x. (End)
Numbers of the form m XOR (2*m) for some m >= 0. - Rémy Sigrist, Feb 07 2021
The terms "evil numbers" and "odious numbers" were coined by Richard K. Guy, c. 1976 (Haque and Shallit, 2016) and appeared in the book by Berlekamp et al. (Vol. 1, 1st ed., 1982). - Amiram Eldar, Jun 08 2021

References

  • Elwyn R. Berlekamp, John H. Conway, Richard K. Guy, Winning Ways for Your Mathematical Plays, Volume 1, 2nd ed., A K Peters, 2001, chapter 14, p. 110.
  • Hugh L. Montgomery, Ten Lectures on the Interface Between Analytic Number Theory and Harmonic Analysis, Amer. Math. Soc., 1996, p. 208.
  • Donald J. Newman, A Problem Seminar, Springer; see Problem #89.
  • Vladimir S. Shevelev, On some identities connected with the partition of the positive integers with respect to the Morse sequence, Izv. Vuzov of the North-Caucasus region, Nature sciences 4 (1997), 21-23 (Russian).
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Complement of A000069 (the odious numbers). Cf. A133009.
a(n)=2*n+A010060(n)=A000069(n)-(-1)^A010060(n). Cf. A018900.
The basic sequences concerning the binary expansion of n are A000120, A000788, A000069, A001969, A023416, A059015.
Cf. A036585 (differences), A010060, A006364.
For primes see A027699, also A130593.

Programs

  • Haskell
    a001969 n = a001969_list !! (n-1)
    a001969_list = [x | x <- [0..], even $ a000120 x]
    -- Reinhard Zumkeller, Feb 01 2012
    
  • Magma
    [ n : n in [0..129] | IsEven(&+Intseq(n,2)) ]; // Sergei Haller (sergei(AT)sergei-haller.de), Dec 21 2006
    
  • Maple
    s := proc(n) local i,j,ans; ans := [ ]; j := 0; for i from 0 while jA001969 := n->t1[n]; # s(k) gives first k terms.
    # Alternative:
    seq(`if`(add(k, k=convert(n,base,2))::even, n, NULL), n=0..129); # Peter Luschny, Jan 15 2021
    # alternative for use outside this sequence
    isA001969 := proc(n)
        add(d,d=convert(n,base,2)) ;
        type(%,'even') ;
    end proc:
    A001969 := proc(n)
        option remember ;
        local a;
        if n = 0 then
            1;
        else
            for a from procname(n-1)+1 do
                if isA001969(a) then
                    return a;
                end if;
            end do:
        end if;
    end proc:
    seq(A001969(n),n=1..200) ; # R. J. Mathar, Aug 07 2022
  • Mathematica
    Select[Range[0,300], EvenQ[DigitCount[ #, 2][[1]]] &]
    a[ n_] := If[ n < 1, 0, With[{m = n - 1}, 2 m + Mod[-Total@IntegerDigits[m, 2], 2]]]; (* Michael Somos, Jun 09 2019 *)
  • PARI
    a(n)=n-=1; 2*n+subst(Pol(binary(n)),x,1)%2
    
  • PARI
    a(n)=if(n<1,0,if(n%2==0,a(n/2)+n,-a((n-1)/2)+3*n))
    
  • PARI
    a(n)=2*(n-1)+hammingweight(n-1)%2 \\ Charles R Greathouse IV, Mar 22 2013
    
  • Python
    def ok(n): return bin(n)[2:].count('1') % 2 == 0
    print(list(filter(ok, range(130)))) # Michael S. Branicky, Jun 02 2021
    
  • Python
    from itertools import chain, count, islice
    def A001969_gen(): # generator of terms
        return chain((0,),chain.from_iterable((sorted(n^ n<<1 for n in range(2**l,2**(l+1))) for l in count(0))))
    A001969_list = list(islice(A001969_gen(),30)) # Chai Wah Wu, Jun 29 2022
    
  • Python
    def A001969(n): return ((m:=n-1).bit_count()&1)+(m<<1) # Chai Wah Wu, Mar 03 2023

Formula

a(n+1) - A001285(n) = 2n-1 has been verified for n <= 400. - John W. Layman, May 16 2003 [This can be directly verified by comparing Ralf Stephan's formulas for this sequence (see below) and for A001285. - Jianing Song, Nov 04 2024]
Note that 2n+1 is in the sequence iff 2n is not and so this sequence has asymptotic density 1/2. - Franklin T. Adams-Watters, Aug 23 2006
a(n) = (1/2) * (4n - 3 - (-1)^A000120(n-1)). - Ralf Stephan, Sep 14 2003
G.f.: Sum_{k>=0} (t(3+2t+3t^2)/(1-t^2)^2) * Product_{l=0..k-1} (1-x^(2^l)), where t = x^2^k. - Ralf Stephan, Mar 25 2004
a(2*n+1) + a(2*n) = A017101(n-1) = 8*n-5.
a(2*n) - a(2*n-1) gives the Thue-Morse sequence (3, 1 version): 3, 1, 1, 3, 1, 3, 3, 1, 1, 3, .... A001969(n) + A000069(n) = A016813(n-1) = 4*n-3. - Philippe Deléham, Feb 04 2004
a(1) = 0; for n > 1: a(n) = 3*n-3 - a(n/2) if n even, a(n) = a((n+1)/2)+n-1 if n odd.
Let b(n) = 1 if sum of digits of n is even, -1 if it is odd; then Shallit (1985) showed that Product_{n>=0} ((2n+1)/(2n+2))^b(n) = 1/sqrt(2).
a(n) = 2n - 2 + A010060(n-1). - Franklin T. Adams-Watters, Aug 28 2006
A005590(a(n-1)) <= 0. - Reinhard Zumkeller, Apr 11 2012
A106400(a(n-1)) = 1. - Reinhard Zumkeller, Apr 29 2012
a(n) = (a(n-1) + 2) XOR A010060(a(n-1) + 2). - Falk Hüffner, Jan 21 2022
a(n+1) = A006068(n) XOR (2*A006068(n)). - Rémy Sigrist, Apr 14 2022

Extensions

More terms from Robin Trew (trew(AT)hcs.harvard.edu)

A014499 Number of 1's in binary representation of n-th prime.

Original entry on oeis.org

1, 2, 2, 3, 3, 3, 2, 3, 4, 4, 5, 3, 3, 4, 5, 4, 5, 5, 3, 4, 3, 5, 4, 4, 3, 4, 5, 5, 5, 4, 7, 3, 3, 4, 4, 5, 5, 4, 5, 5, 5, 5, 7, 3, 4, 5, 5, 7, 5, 5, 5, 7, 5, 7, 2, 4, 4, 5, 4, 4, 5, 4, 5, 6, 5, 6, 5, 4, 6, 6, 4, 6, 7, 6, 7, 8, 4, 5, 4, 5, 5, 5, 7, 5, 7, 7, 4, 5, 6, 7, 6, 8, 7, 7, 7, 8, 8, 3, 4
Offset: 1

Views

Author

Ingemar Assarsjo (ingemar(AT)binomen.se)

Keywords

Comments

a(n) is the rank of prime(n) in the base-2 dominance order on the natural numbers. - Tom Edgar, Mar 25 2014

Examples

			From _M. F. Hasler_, Mar 03 2023: (Start)
a(n) = 1 only for p(n = 1) = 2, the only prime equal to a power of 2.
a(n) = 2 for n in A159611 = A000720(A019434) = {2, 3, 7, 55, 6543} (probably complete), the Fermat primes F[k] = 2^2^k + 1 with k = 0, 1, 2, 3, 4. (On the graph one can distinctly see a(6543) = 2 corresponding to F[4] = 65537.)
a(n) = 3 for n in A000720(A081091) = (4, 5, 6, 8, 12, 13, 19, 21, 25, 32, 33, 44, 98, 106, 116, 136, 174, 191, 310, 313, 319, 565, 568, ...). (End)
		

Crossrefs

Cf. A180024. - Reinhard Zumkeller, Aug 08 2010
Cf. A072084.
Cf. A159611 (indices of 2s), A000720(A081091) (indices of 3s). - M. F. Hasler, Mar 03 2023

Programs

  • Haskell
    a014499 = a000120 . a000040  -- Reinhard Zumkeller, Feb 10 2013
    
  • Magma
    [&+Intseq(NthPrime(n), 2): n in [1..100] ]; // Vincenzo Librandi, Mar 25 2014
    
  • Mathematica
    Table[Plus @@ IntegerDigits[Prime[n], 2], {n, 1, 100}] (* Vincenzo Librandi, Mar 25 2014 *)
  • PARI
    A014499(n)=hammingweight(prime(n)) \\ M. F. Hasler, Nov 20 2009, updated Mar 03 2023
    
  • Python
    from sympy import prime
    def A014499(n): return prime(n).bit_count() # Chai Wah Wu, Mar 22 2023
  • Sage
    [sum(i.digits(base=2)) for i in primes_first_n(200)] # Tom Edgar, Mar 25 2014
    

Formula

a(n) = A000120(A000040(n)).
a(A049084(A061712(n))) = n. - Reinhard Zumkeller, Feb 10 2013
a(n) = [x^prime(n)] (1/(1 - x))*Sum_{k>=0} x^(2^k)/(1 + x^(2^k)). - Ilya Gutkovskiy, Mar 27 2018

A027697 Odious primes: primes with odd number of 1's in binary expansion.

Original entry on oeis.org

2, 7, 11, 13, 19, 31, 37, 41, 47, 59, 61, 67, 73, 79, 97, 103, 107, 109, 127, 131, 137, 151, 157, 167, 173, 179, 181, 191, 193, 199, 211, 223, 227, 229, 233, 239, 241, 251, 271, 283, 307, 313, 331, 367, 379, 397, 409, 419, 421, 431, 433, 439, 443, 457, 463, 487, 491, 499, 521, 541, 557, 563
Offset: 1

Views

Author

Keywords

Comments

Conjecture: a(n) < A027699(n) except for n = 2; verified up to n=5*10^7. Moreover, I conjecture that A027699(n) - a(n) tends to infinity. - Vladimir Shevelev

Crossrefs

Cf. A000069 (odious numbers), A092246 (odd odious numbers)

Programs

  • Maple
    a:=proc(n) local nn: nn:= convert(ithprime(n), base, 2): if `mod`(sum(nn[j], j =1..nops(nn)), 2)=1 then ithprime(n) else end if end proc: seq(a(n),n=1..103); # Emeric Deutsch, Oct 24 2007
  • Mathematica
    Clear[BinSumOddQ];BinSumOddQ[a_]:=Module[{i,s=0},s=0;For[i=1,i<=Length[IntegerDigits[a,2]],s+=Extract[IntegerDigits[a,2],i];i++ ];OddQ[s]]; lst={};Do[p=Prime[n];If[BinSumOddQ[p],AppendTo[lst,p]],{n,4!}];lst (* Vladimir Joseph Stephan Orlovsky, Apr 06 2009 *)
    Select[Prime@ Range@ 120, OddQ@ First@ DigitCount[#, 2] &] (* Michael De Vlieger, Feb 08 2016 *)
  • PARI
    f(p)={v=binary(p);s=0;for(k=1,#v,if(v[k]==1,s++));return(s%2)};
    forprime(p=2, 563, if(f(p), print1(p,", "))) \\ Washington Bomfim, Jan 14 2011
    
  • PARI
    s=[]; forprime(p=2, 1000, if(norml2(binary(p))%2==1, s=concat(s, p))); s \\ Colin Barker, Feb 18 2014
    
  • Python
    from sympy import primerange
    print([n for n in primerange(1, 1001) if bin(n)[2:].count("1")%2]) # Indranil Ghosh, May 03 2017

Extensions

More terms from Scott Lindhurst (ScottL(AT)alumni.princeton.edu)

A091209 Primes whose binary representation encodes a polynomial reducible over GF(2).

Original entry on oeis.org

5, 17, 23, 29, 43, 53, 71, 79, 83, 89, 101, 107, 113, 127, 139, 149, 151, 163, 173, 179, 181, 197, 199, 223, 227, 233, 251, 257, 263, 269, 271, 277, 281, 293, 307, 311, 317, 331, 337, 347, 349, 353, 359, 367, 373, 383, 389, 401, 409, 421, 431, 439, 443, 449, 457, 461, 467, 479, 491, 503, 509, 521, 523
Offset: 1

Views

Author

Antti Karttunen, Jan 03 2004

Keywords

Comments

"Encoded in binary representation" means that a polynomial a(n)*X^n+...+a(0)*X^0 over GF(2) is represented by the binary number a(n)*2^n+...+a(0)*2^0 in Z (where each coefficient a(k) = 0 or 1).
Except for 3, all primes with even Hamming weight (A027699) are terms, see A238186 for the subsequence of primes with odd Hamming weight. [Joerg Arndt and Antti Karttunen, Feb 19 2014]

Crossrefs

Intersection of A000040 and A091242.
Disjoint union of A238186 and (A027699 \ {3}).
Left inverse: A235043.
Cf. A091206 (Primes whose binary expansion encodes a polynomial irreducible over GF(2)), A091212 (Composite, and reducible over GF(2)), A091214 (Composite, but irreducible over GF(2)).

Programs

  • Maple
    Primes:= select(isprime,[2,seq(2*i+1,i=1..1000)]):
    filter:= proc(n) local L,x;
        L:= convert(n,base,2);
        Irreduc(add(L[i]*x^(i-1),i=1..nops(L))) mod 2;
    end proc:
    remove(filter,Primes); # Robert Israel, May 17 2015
  • Mathematica
    Select[Prime[Range[2, 100]], !IrreduciblePolynomialQ[bb = IntegerDigits[#, 2]; Sum[bb[[k]] x^(k-1), {k, 1, Length[bb]}], Modulus -> 2]&] (* Jean-François Alcover, Feb 28 2016 *)
  • PARI
    forprime(p=2, 10^3, if( ! polisirreducible( Mod(1,2)*Pol(binary(p)) ), print1(p,", ") ) ); \\ Joerg Arndt, Feb 19 2014

Formula

a(n) = A000040(A091210(n)) = A091242(A091211(n)).
Other identities. For all n >= 1:
A235043(a(n)) = n. [A235043 works as a left inverse of this sequence.]
Showing 1-10 of 37 results. Next