A239937 - OEIS

A239937

Numbers k such that DigitSum(k^2) > DigitSum((k+1)^2).

3, 7, 8, 9, 14, 17, 19, 24, 26, 28, 29, 31, 33, 34, 37, 38, 39, 43, 44, 47, 48, 53, 54, 57, 59, 63, 64, 67, 69, 70, 74, 77, 78, 79, 83, 84, 87, 88, 89, 93, 94, 97, 98, 99, 104, 107, 109, 114, 117, 118, 119, 122, 124, 126, 128, 129, 133, 134, 137, 138, 141, 143

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..62.

EXAMPLE

For k=3, we have DigitSum(3^2) = 9 > 7 = DigitSum(4^2).

MATHEMATICA

lis = Table[Total[IntegerDigits[n^2, 10]], {n, 1, 100}];

Flatten[Position[Greater @@@ Partition[lis, 2, 1], True]]

Position[Partition[Total[IntegerDigits[#]]&/@(Range[150]^2), 2, 1], _?(#[[1]]> #[[2]]&), 1, Heads->False]//Flatten (* Harvey P. Dale, Feb 19 2020 *)

PROG

(PARI) isok(k) = sumdigits(k^2) > sumdigits((k+1)^2); \\ Michel Marcus, Jul 03 2021

CROSSREFS

Cf. A007953 (sum of digits of n), A004159 (sum of digits of n^2).

Sequence in context: A298984 A094551 A342006 * A375019 A114441 A354023

Adjacent sequences: A239934 A239935 A239936 * A239938 A239939 A239940

KEYWORD

nonn,base

AUTHOR

Oliver Bel, Mar 29 2014

EXTENSIONS

More terms from Jon E. Schoenfield, Mar 29 2014

STATUS

approved