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 1-5 of 5 results.

A063114 a(n) = n + product of the nonzero digits of n.

Original entry on oeis.org

2, 4, 6, 8, 10, 12, 14, 16, 18, 11, 12, 14, 16, 18, 20, 22, 24, 26, 28, 22, 23, 26, 29, 32, 35, 38, 41, 44, 47, 33, 34, 38, 42, 46, 50, 54, 58, 62, 66, 44, 45, 50, 55, 60, 65, 70, 75, 80, 85, 55, 56, 62, 68, 74, 80, 86, 92, 98, 104, 66, 67, 74, 81, 88, 95, 102, 109, 116
Offset: 1

Views

Author

N. J. A. Sloane, Aug 08 2001

Keywords

Examples

			a(59) = 59 + 5*9 = 104. a(66) = 66 + 6*6 = 102.
		

Crossrefs

Programs

  • ARIBAS
    var stk: stack; end; for n := 1 to 80 do s := itoa(n); for j := 0 to length(s) -1 do k := atoi(s[j..j]); if k > 0 then stack_push(stk,k); end; end; write(n + product(stack2array(stk))," "); end;
    
  • Haskell
    a063114 n = n + a051801 n -- Reinhard Zumkeller, Jan 15 2012
  • Mathematica
    Table[i+Times@@(IntegerDigits[i]/. 0->1), {i, 70}]
  • PARI
    a(n) = n + vecprod(select(x->(x!=0), digits(n))) \\ Harry J. Smith, Aug 19 2009
    

Formula

a(n) = n + A051801(n). - Reinhard Zumkeller, Jan 15 2012

Extensions

More terms from Robert G. Wilson v and Klaus Brockhaus, Aug 09 2001

A062329 a(n) = (sum of digits of n) - (product of digits of n).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 0, -1, -2, -3, -4, -5, -6, -7, 3, 1, -1, -3, -5, -7, -9, -11, -13, -15, 4, 1, -2, -5, -8, -11, -14, -17, -20, -23, 5, 1, -3, -7, -11, -15, -19, -23, -27, -31, 6, 1, -4, -9, -14, -19, -24, -29, -34, -39, 7, 1, -5, -11, -17, -23, -29, -35, -41, -47, 8, 1, -6, -13, -20, -27
Offset: 0

Views

Author

Amarnath Murthy, Jun 21 2001

Keywords

Examples

			a(23) = 2 + 3 - 2*3 = -1.
a(49) = -(4*9) + (4 + 9) = -36 + 13 = -23.
		

Crossrefs

Programs

  • Mathematica
    a[n_] := (t = IntegerDigits[n]; Plus @@ t - Times @@ t); Table[ a[n], {n, 0, 75}] (* Robert G. Wilson v *)

Extensions

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jun 22 2001
Signed version from Henry Bottomley, Jun 29 2001

A233783 The smallest prime that produces a set of n primes such that every prime after the first one is equal to the previous minus the product of its nonzero digits.

Original entry on oeis.org

2, 23, 251, 347, 5023, 50227, 64037, 3924211, 4952767, 43275737, 586635689, 592856489, 62527264517
Offset: 1

Views

Author

Carlos Rivera, Dec 15 2013

Keywords

Comments

a(14) > 6.8*10^11. - Giovanni Resta, Dec 16 2013

Examples

			Example: for n = 3, initial prime is 251, because 251 -> 251 - 2*5*1 = 241 -> 241 - 2*4*1 -> 233.
		

Crossrefs

Extensions

a(11)-a(13) from Giovanni Resta, Dec 16 2013

A246622 Primes of the form n + product of nonzero digits of n, in order of their occurrence.

Original entry on oeis.org

2, 11, 23, 29, 41, 47, 67, 109, 89, 107, 101, 167, 181, 223, 199, 227, 251, 293, 283, 349, 331, 433, 347, 461, 313, 383, 353, 379, 431, 457, 379, 443, 521, 547, 457, 491, 593, 499, 557, 673, 601, 823, 619, 653, 839, 607, 617, 631, 659, 673, 659, 743, 929, 919
Offset: 1

Views

Author

K. D. Bajpai, Aug 31 2014

Keywords

Comments

Primes in A063114.

Examples

			a(2) = 11 which is prime. Also, 11 = 10 + 1, which is n + product of nonzero digit of n.
a(9) = 89 which is prime. Also, 89 = 81 + (8*1), which is n + product of nonzero digits of n.
a(10) = 107 which is prime. Also, 107 = 83 + (8*3), which is n + product of nonzero digits of n.
		

Crossrefs

Programs

  • Mathematica
    Select[Table[n + Times @@ DeleteCases[IntegerDigits[n], 0], {n, 1000}], PrimeQ]

A329725 a(1)=0, a(n) = n - (product of nonzero digits of n) - a(n-1).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 9, 1, 9, 1, 9, 1, 9, 1, 9, 1, 17, 2, 16, 1, 15, 0, 14, -1, 13, -2, 29, -1, 27, -3, 25, -5, 23, -7, 21, -9, 45, -8, 42, -11, 39, -14, 36, -17, 33, -20, 65, -19, 61, -23, 57, -27, 53, -31, 49, -35, 89, -34, 84, -39, 79, -44, 74, -49, 69, -54, 117
Offset: 1

Views

Author

Joshua Oliver, Nov 19 2019

Keywords

Comments

a(10n+1)-a(10n-1)=1 for all positive integer n (conjectured).

Examples

			a(22) = 22 - 2*2 - 2 = 16.
		

Crossrefs

Programs

  • Maple
    R:= ListTools:-PartialSums(map(n -> (-1)^n*(n - convert(subs(0=NULL,convert(n,base,10)),`*`)), [$1..100])):
    seq((-1)^n*R[n],n=1..100); # Robert Israel, Nov 20 2019
  • Mathematica
    Nest[Append[#1, #2 - Last[#1] - Times @@ DeleteCases[IntegerDigits[#2], 0]] & @@ {#, Length@ # + 1} &, {0}, 69] (* Michael De Vlieger, Nov 19 2019 *)
  • PARI
    for (n=1, 70, print1 (v=if (n==1, 0, n - vecprod(select(sign, digits(n))) - v)", ")) \\ Rémy Sigrist, Nov 28 2019

Formula

a(n) = Sum_{k=2..n} (-1)^(n-k)*A063543(k). - Robert Israel, Nov 20 2019
Showing 1-5 of 5 results.