A062918 - OEIS

A062918

Sum of the digit reversals of the first n natural numbers.

1, 3, 6, 10, 15, 21, 28, 36, 45, 46, 57, 78, 109, 150, 201, 262, 333, 414, 505, 507, 519, 541, 573, 615, 667, 729, 801, 883, 975, 978, 991, 1014, 1047, 1090, 1143, 1206, 1279, 1362, 1455, 1459, 1473, 1497, 1531, 1575, 1629, 1693, 1767, 1851, 1945, 1950, 1965

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

OFFSET

1,2

COMMENTS

a(n) = A000217(n) for n=1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 86, 89, ...; checked up to 10^7. - Michel Marcus, Sep 15 2015; checked up to 2^32 ~ 4*10^9. - Kenny Lau, Aug 01 2017

LINKS

Harry J. Smith, Table of n, a(n) for n=1..1000

EXAMPLE

a(12) = 78 as 1+2+3+4+5+6+7+8+9+R(10)+R(11)+R(12) = 1+2+3+4+5+6+7+8+9+01+11+21 = 78.

MATHEMATICA

Accumulate[Table[FromDigits[Reverse[IntegerDigits[n]]], {n, 1, 120}]] (* Enrique Pérez Herrero, Jun 01 2013 *)

Accumulate[IntegerReverse[Range[60]]] (* Harvey P. Dale, Dec 25 2021 *)

PROG

(PARI) { a=0; for (n=1, 1000, x=n; r=0; while (x>0, d=x-10*(x\10); x\=10; r=r*10 + d); write("b062918.txt", n, " ", a+=r) ) } \\ Harry J. Smith, Aug 12 2009

(PARI) a(n) = sum(k=1, n, eval(concat(Vecrev(Str(k))))); \\ Michel Marcus, Sep 15 2015

CROSSREFS

Cf. A000217, A004086, A069792.

Sequence in context: A109453 A217627 A037123 * A113168 A341192 A071817

Adjacent sequences: A062915 A062916 A062917 * A062919 A062920 A062921

KEYWORD

nonn,base,easy

AUTHOR

Amarnath Murthy, Jul 02 2001

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Jul 05 2001

STATUS

approved