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A062398 Numbers such that the product of the digits and the sum of the digits are squares. 2
1, 4, 9, 10, 22, 40, 88, 90, 100, 103, 108, 130, 144, 180, 202, 207, 220, 270, 301, 306, 310, 360, 400, 405, 414, 441, 450, 466, 504, 540, 603, 630, 646, 664, 702, 709, 720, 790, 801, 808, 810, 880, 889, 898, 900, 907, 970, 988, 1000, 1003, 1008, 1012, 1017 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

EXAMPLE

144 belongs to the sequence as sum of digits = 9 and the product of the digits = 16.

MATHEMATICA

pdsdQ[n_]:=Module[{idn=IntegerDigits[n]}, IntegerQ[Sqrt[Total[idn]]] && IntegerQ[Sqrt[Times@@idn]]]; Select[Range[1100], pdsdQ] (* Harvey P. Dale, Aug 20 2012 *)

PROG

(PARI) SumD(x)= { s=0; while (x>9, s+=x-10*(x\10); x\=10); return(s + x) } ProdD(x)= { p=1; while (x>9, p*=(x-10*(x\10)); x\=10); return(p*x) } { n=0; for (m=1, 10^9, if (issquare(ProdD(m)) && issquare(SumD(m)), write("b062398.txt", n++, " ", m); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 07 2009

CROSSREFS

Sequence in context: A061766 A109448 A177927 * A030754 A244863 A077584

Adjacent sequences:  A062395 A062396 A062397 * A062399 A062400 A062401

KEYWORD

nonn,base,easy

AUTHOR

Amarnath Murthy, Jun 28 2001

EXTENSIONS

Corrected and extended by Erich Friedman, Jul 02 2001

STATUS

approved

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Last modified November 22 08:46 EST 2019. Contains 329389 sequences. (Running on oeis4.)