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A114570 Let the decimal expansion of n be d_1 d_2 ... d_k; then a(n) = Sum_{i=1..k} d_i^(k+1-i). 3
1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 49, 50, 51, 52, 53, 54, 55, 56, 57 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Every number n (of two or more digits) is guaranteed to yield a smaller number a(n) since 9^k < 10^k This sequence is related to other sequences about sum of the digits or sum of powers of digits.

LINKS

Table of n, a(n) for n=1..78.

EXAMPLE

E.g. a(1247) = 1^4 + 2^3 + 4^2 + 7^1 = 1 + 8 + 16 + 7 = 32.

MAPLE

A114570 := proc(n) local L; L := convert(n, base, 10) ; add( op(i, L)^i, i=1..nops(L)) ; end proc: # R. J. Mathar, Dec 20 2010

MATHEMATICA

f[n_] := Block[{id = IntegerDigits@ n}, Plus @@ (id^Reverse@ Range@ Length@ id)]; Array[f, 78]

PROG

(Sage) A114570 = lambda n: sum(d**i for i, d in enumerate(n.digits(), 1)) # D. S. McNeil, Dec 21 2010

(PARI) a(n) = my(d=digits(n), k=#d); sum(i=1, k, d[i]^(k+1-i)); \\ Michel Marcus, Jan 25 2018

CROSSREFS

Sequence in context: A007953 A080463 A209685 * A247796 A326344 A115026

Adjacent sequences:  A114567 A114568 A114569 * A114571 A114572 A114573

KEYWORD

nonn,base

AUTHOR

Sergio Pimentel, Feb 16 2006

STATUS

approved

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Last modified October 15 03:32 EDT 2019. Contains 328026 sequences. (Running on oeis4.)