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A116172 Numbers k such that k concatenated with k+2 gives the product of two numbers which differ by 5. 11
2, 74, 59264, 510782, 906902, 81790664, 92776472, 10876856041862, 11796926254874, 18332259798794, 18388650720624, 32624670587648, 32699883214248, 43103618706398, 44916698243804, 66132258426302 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Also numbers k such that k concatenated with k+6 gives the product of two numbers which differ by 3.

Also numbers k such that k concatenated with k+8 gives the product of two numbers which differ by 1.

If k+2 and k-4 have the same number of digits, then k is also in A116132 because k//k+2 = 10^d*k + k + 2 = m*(m+5) then implies k//k-4 = 10^d*k + k - 4 = m*(m+5) - 6 = (m-1)*(m+6). - R. J. Mathar, Aug 10 2008

LINKS

Table of n, a(n) for n=1..16.

EXAMPLE

92776472//92776474 = 96320542 * 96320547, where // denotes concatenation.

92776472//92776480 = 96320544 * 96320545.

92776472//92776478 = 96320543 * 96320546.

CROSSREFS

Cf. A116158, A116171, A116173, A116179, A116303.

Cf. A116185, A115430, A116205, A116343, A116200, A116330.

Sequence in context: A322281 A282878 A062552 * A238820 A000329 A091978

Adjacent sequences:  A116169 A116170 A116171 * A116173 A116174 A116175

KEYWORD

nonn,base

AUTHOR

Giovanni Resta, Feb 06 2006

EXTENSIONS

Edited by N. J. A. Sloane, Apr 15 2007

STATUS

approved

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Last modified August 4 10:11 EDT 2021. Contains 346447 sequences. (Running on oeis4.)