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.

A263535 a(1) = 1; thereafter a(n) = a(n-1) + d_1^1 + d_2^2 + d_3^3 + ..., where d_1 d_2 d_3 ... is the decimal expansion of a(n-1).

Original entry on oeis.org

1, 2, 4, 8, 16, 53, 67, 122, 135, 270, 321, 329, 1065, 1907, 4390, 5132, 5181, 5700, 5754, 6189, 13269, 73632, 73977, 93930, 94758, 128519, 661103, 661876, 729478, 1009425, 1095200, 1096587, 2187425, 2269554, 2311471, 2430158, 4542981, 4864284, 5143384, 5422306
Offset: 1

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Author

Pieter Post, Oct 20 2015

Keywords

Comments

This additive sequence will tend to be geometric.

Examples

			a(5)=16, so a(6) is 16 + 1^1 + 6^2 = 53.
		

Crossrefs

Programs

  • Mathematica
    NestList[#+Total[IntegerDigits[#]^Range[IntegerLength[#]]]&,1,40] (* Harvey P. Dale, Jan 19 2021 *)
  • PARI
    lista(nn) = {print1(a=1, ", "); for (n=2, nn, d = digits(a); na = a + sum(i=1, #d, d[i]^i); print1(na, ", "); a = na;);} \\ Michel Marcus, Nov 20 2015
  • Python
    def moda(n):
        return sum(int(d)**(i + 1) for i, d in enumerate(str(n)))
    b = 1
    resu = [1]
    for a in range(1, 100):
        b += moda(b)
        resu.append(b)
    resu
    
  • Sage
    A=[1]
    for i in [1..2000]:
        A.append(A[i-1]+sum(A[i-1].digits()[len(A[i-1].digits())-1-j]^(j+1) for j in [0..len(A[i-1].digits())-1]))
    A # Tom Edgar, Oct 20 2015