The On-Line Encyclopedia of Integer Sequences (OEIS)

A066003 revision #19

A066003

Sum of digits of 7^n.

1, 7, 13, 10, 7, 22, 28, 25, 31, 28, 43, 49, 37, 52, 58, 64, 52, 58, 73, 79, 76, 82, 97, 85, 73, 97, 112, 91, 133, 121, 118, 115, 103, 127, 142, 157, 136, 115, 130, 136, 142, 148, 136, 169, 175, 163, 187, 175, 136, 178, 184, 217, 196, 220, 217

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Harry J. Smith, Table of n, a(n) for n=0,...,1000

FORMULA

a(n) = A007953(A000420(n)). - Michel Marcus, Nov 01 2013

MATHEMATICA

Table[Total[IntegerDigits[7^n]], {n, 55}] (* Harvey P. Dale, Nov 22 2010 *)

PROG

(MAGMA) [ &+Intseq(7^n): n in [0..60] ];

(PARI) SumD(x)= { local(s=0); while (x>9, s+=x%10; x\=10); return(s + x) }

{ for (n=0, 1000, a=SumD(7^n); write("b066003.txt", n, " ", a) ) } \\ Harry J. Smith, Nov 06 2009

(PARI) a(n) = sumdigits(7^n); \\ Michel Marcus, Nov 01 2013

CROSSREFS

Cf. A000420 (7^n), A007953 (sum of digits).

Cf. sum of digits of k^n: A001370 (k=2), A004166 (k=3), A065713 (k=4), A066001 (k=5), A066002 (k=6), this sequence (k=7), A066004 (k=8), A065999 (k=9), A066005 (k=11), A066006 (k=12), A175527 (k=13).

Sequence in context: A365346 A215990 A122874 * A115858 A114389 A259232

Adjacent sequences: A066000 A066001 A066002 * A066004 A066005 A066006

KEYWORD

nonn,base

AUTHOR

N. J. A. Sloane, Dec 11 2001

STATUS

editing